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Bureau of Mines Information Circular/1985 



Critical and Strategic 
Minerals in Alaska 

Tin, Tantalum, and Columbium 

By J. Dean Warner 




UNITED STATES DEPARTMENT OF THE INTERIOR 



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Information Circular 9037 

A 



Critical and Strategic 
Minerals in Alaska 

Tin, Tantalum, and Columbium 



By J. Dean Warner 




UNITED STATES DEPARTMENT OF THE INTERIOR 
Donald Paul Hodel, Secretary 

BUREAU OF MINES 
Robert C. Horton, Director 



As the Nation's principal conservation agency, the Department of the 
Interior has responsibility for most of our nationally owned public lands 
and natural resources. This includes fostering the wisest use of our land 
and water resources, protecting our fish and wildlife, preserving the 
environmental and cultural values of our national parks and historical 
places, and providing for the enjoyment of life through outdoor recreation. 
The Department assesses our energy and mineral resources and works to 
assure that their development is in the best interests of all our people. The 
Department also has a major responsibility for American Indian reserva- 
tion communities and for people who live in island territories under U.S. 
administration. , „ • 



Library of Congrats Cataloging In Publication data 




Warner, J. Dean 

Critical and strategic minerals in Alaska. 

(Bureau of Mines information circular; 9037) 
Bibliography: p. 8 
Supt. of Docs, no.: I 28.27: 

1. Tin— Alaaka. 2. Tantalum — Alaska. 3. Niobium — Alaska. I. Title. II. Series: Infor 
madon circular (United States. Bureau of Mines; 9037. 



TN295.U4 (TN271.T5) 



622 s 



(553.4'53'09798] ?f g™"""* 



For sale by the Superintendent of Documents, U.S. Government Printing Office 
Washington, DC 20402 



Ill 



CONTENTS 



O 

o 



Page 

Abstract 1 

Introduction 2 

Acknowledgments 2 

Definitions 2 

History, production, and reserves 2 

Tin 2 

Tantalum and columbium 4 

Bureau of Mines investigations 4 

Trends of Alaskan tin occurrences 4 

Alaska Range 4 

Yukon-Tanana 4 

Kuskokwim 5 

Kokrine-Hodzana 5 

Seward Peninsula 5 

Northeast Alaska and Brooks Range 5 

Other areas with tin occurrences 5 



Page 

Tin lode occurrences 5 

Greisen 5 

Vein 5 

Skarn 5 

Pegmatite 6 

Volcanogenic massive sulfide 6 

Tin placer occurrences 6 

Regional features of Alaskan tantalum and 

columbium occurrences 6 

Tantalum and columbium lode occurrences 6 

Tantalum and columbium placer occurrences 7 

Summary 7 

References 8 

Appendix. — Listings of lode and placer occurrences 

of tin, tantalum, and columbium in Alaska 11 



ILLUSTRATION 



1 . Tin. tantalum, and columbium occurrences in Alaska in pocket 



TABLES 



1 . Estimated production of tin from lode and placer sources in Alaska 3 

2. Tin reserves in Alaskan lode and placer deposits 3 

A-1 . Lode occurrences 11 

A-2. Placer occurrences 15 



IV 



UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT 



ft 


foot 


ft 2 


square foot 


in 


inch 


lb 


pound 


lb/yd 3 


pound per cubic yard 


Ib/yr 


pound per year 


m 


meter 


mg 


milligram 



mi mile 

MM lb million pounds 

MMyr million years 

oz/ton ounce per ton 

pet percent 

ppm part per million 

yd 3 cubic yard 



CRITICAL AND STRATEGIC MINERALS IN ALASKA 
Tin, Tantalum, and Columbium 

By J. Dean Warner 1 
ABSTRACT 



Alaska contains many critical and strategic minerals that are scarce in the conterminous United 
States. Among these are tin, tantalum, and columbium. This Bureau of Mines report summarizes 
available data on the production, reserves, and occurrences of these minerals in Alaska. 

Alaska produces about 200,000 lb of tin per year, with historical production since 1 901 estimated 
to have totaled 5,830,600 lb. Measured, indicated, and inferred tin reserves total over 140,o6o,000 lb. 
Much of the tin production has been from the placer mines of the western Seward Peninsula; 
however, most of the reserves are in that area's lode deposits. 

Alaskan tin occurrences are part of a belt of tin mineralization that extends along the western 
coast of North and South America. The Alaskan portion of this "tin belt" comprises placer occurrences 
and lode occurrences of five major types: greisen, vein, skarn, pegmatite, and volcanogenic massive 
sulfide. Greisen and vein occurrences are the most abundant, but skarn deposits have historically 
been the most economically important. 

Columbium and tantalum have not been produced in Alaska; however, they may be recoverable 
as byproducts of tin, tungsten, gold, or uranium mining. Approximately 1 35,000 lb of columbium oxide 
(Cb 2 5 ) are inferred within the Tofry placer deposits in the Manley Hot Springs district. 



' Geologist. Alaska Field Operations Center. Bureau of Mines, Fairbanks, AK. 



INTRODUCTION 



Alaska has frequently been a source of tin, tungsten, 
platinum-group metals, antimony, mercury, chromite, and 
small amounts of asbestos during periods of national 
shortage, including the First and Second World Wars and the 
Korean and Vietnam conflicts. In a program that is part of the 
mineral studies mandated under the Alaska National Interest 
Lands Conservation Act (ANILCA), 2 the Bureau of Mines is 
evaluating occurrences of critical and strategic minerals in 
Alaska. The objective of this program is to locate deposits 



that could be mined if a prolonged national shortage should 
develop. Field work undertaken in 1981 concentrated on 
cobalt, platinum-group metals, and chromite (1). 3 This report 
presents findings from the second phase of the Bureau's 
critical and strategic minerals program in Alaska; it summa- 
rizes information on tin, tantalum, and columbium production, 
reserves, and occurrences. This information is meant to 
serve as a basis for future field and laboratory research. 



ACKNOWLEDGMENTS 



The mineral occurrence map (fig. 1, in pocket) and the 
mineral occurrence data presented in this report were 
compiled principally from the published sources listed in the 
reference section and from the computerized files of the 
Bureau of Mines Minerals Availability System (MAS). In 
addition, the following companies provided prospect informa- 



tion and/or assisted the author in obtaining prospect 
information: Anaconda Minerals Co., Bear Creek Mining Co., 
Duval Corp., Patino, Inc., and Tenneco Minerals Co., 
Anchorage, AK; Resource Associates of Alaska, Inc. and 
Doyon Ltd., Fairbanks, AK; Billiton Exploration, Inc., Denver, 
CO; and Union Carbide Corp., Grand Junction, CO. 



DEFINITIONS 



This report uses the following definitions: 

Occurrence - The verifiable presence of a mineral or 
minerals. 

Prospect - A mineral property, the value of which has not 
been proved by exploration. 

Deposit - A natural occurrence of a useful mineral of 
sufficient extent and degree of concentration to invite 
exploration. 

Mine - An opening or excavation in the earth for the 
purpose of extracting minerals. 



Cassiterite (Sn0 2 ) is the most abundant tin mineral and 
the only tin-ore mineral produced in Alaska. Some reports of 
tin production list pounds of concentrate, some pounds of 
cassiterite, and some pounds of tin metal. In this report, 
unless otherwise noted, concentrate is assumed to contain 
75 pet Sn metal, which is essentially the same as the tin 
content, by weight, of cassiterite. This assumption probably 
results in a slight overestimation of total tin production, but is 
used as an upper limit for the tin content of concentrates 
where no specific information is available. 4 



HISTORY, PRODUCTION, AND RESERVES 



TIN 

Tin was first reported in Alaska in 1900 by A. H. Brooks 
of the U.S. Geological Survey (USGS), who identified 
cassiterite in placer concentrates from Buckner Creek and 
the Anikovik River on the Seward Peninsula (2-3). Followup 
exploration led to the location of tin placer deposits near 
Potato, Cape, Ear, and Brooks Mountains and later to the 
discovery of lode-tin occurrences in the same areas. 

The largest of the lode discoveries was the Lost River 
Mine (map location 13 s ) near Brooks Mountain, which yielded 
695,400 lb Sn metal during intermittent operation from 1901 
to 1964 (4), as shown in table 1. The Lost River Mine and 
minor production from lodes at Cape Mountain (map location 
12) and possibly at Potato Mountain (map location 11) 
account for all Alaskan lode tin production. 

Most Alaskan tin production has come from placer 
mines, and most of this production has been derived from 
Buck and Grouse Creeks in the Potato Mountain area, and 
Cape Creek in the Cape Mountain area, on the western 
Seward Peninsula (4). (See table 1.) Since the commence- 



2 Public Law 96-487, Dec. 2, 1980, title 10, section 1010. 

3 Italic numbers in parentheses refer to items in the list of references 
preceding the appendix. 

4 Of the total 5,830,600 lb Sn production reported later in the text, 
approximately 12,500 lb was derived using the 75-pct assumption. 



ment of mining, the combined production of placer tin from 
these two areas has totaled an estimated 4,292,000 lb. 

Following the discovery of tin on the Seward Peninsula, 
cassiterite was identified in concentrates from several gold 
mining districts in interior Alaska. The most productive was 
near Tofty (map location 36), in the Manley Hot Springs 
district, where shipments of placer cassiterite concentrate 
from bench gravels commenced in 1911 (11). Intermittent 
production from this area through 1982 accounted for 
approximately 400,000 lb Sn, 6 or approximately 7 pet of total 
Alaskan tin production (table 1). Minor production of tin also 
has been reported from the Ruby (map location 32), Circle 
(map location 33), and Melozitna mining districts (map 
locations 29-31) of interior Alaska. 

Alaskan tin production is estimated to have totaled 
approximately 5,830,600 lb to 1983. Tin production from 
Cape Creek and Tofty was estimated to have totaled 
approximately 198,000 lb in 1982 and 215,000 lb in 1983 
(7-8, 72). The 1 983 output from these two areas was equal to 



5 All references to map locations refer to locations shown in figure 1 (map in 
pocket). In addition, both lode and placer occurrences are described in 
appendix tables A-1 and A-2. 

f Production estimates by Wayland (19) for the Tofty area are higher than 
those by Thomas (11), which were used to calculate this figure. Wayland 
estimates 352,600 lb Sn production through 1941, with little additional 
production from 1941 through 1961, while Thomas estimates 282,000 lb Sn 
production through 1956. 



Table 1.— Estimated production' of tin from lode and placer sources in Alaska 



Source 

(placer sources unless 

otherwise specified) 



Map 
location 
(fig. 1) 



Period 



Reported production, lb 
(concentrate unless 
otherwise specified) 



References 



SEWARD PENINSULA 



Lode sources: 

Lost River Mine area 

Cape Mountain 

Potato Mountain 

Lost River Mine area 

Do 

Cape Mountain area 

Do 
Potato Mountain area 

Oner Creek 

Others 

Total. Seward Peninsula 



13 
12 
11 
13 
13 
12 
12 
11 
18 
NAp 
NAp 



1901-64 
1901-64 
1902-53 
1901-64 
1964-65 
1924-75 
1979-82 
1901-64 
To 1 964 
U 
1901-82 



695.400 

12,000 

2,000 

187,296 

( 2 ) 

1,537,000 

= 765,250 

2,204,600 

( 3 ) 

< 1,000 

s 5.400.000 



(Sn metal) 
(Sn metal) 
(Sn metal) 
(Sn metal) 

(Sn metal) 
(Sn metal) 
(Sn metal) 

(Sn metal) 
(Sn metal) 



4-5 

5-8 

4 

9 

10 

NAp 



TOFTY TIN BELT. MANLEY HOT SPRINGS DISTRICT 



Cache Creek 

Dalton Creek 

L/6€u v c6K 

Deep Creek tnbutanes 

Idaho Gulch 

Miller Gulch 

Patterson Creek 

Sullivan Creek 

Tofty Gulch 

Woodchopper Creek. . 
Unspecified sources 
Total. Tofty tin beir 1 



36 



NAp 



1 906-56 



' 1966-82 
1906-82 



5,155 

3,000 

56,200 

8,000 

300 

101,875 

20,282 

215,445 

19,600 

40,300 

> 120,000 (Sn metal) 

=402,100 (Sn metal) 



10 



12 
NAp 



RUBY DISTRICT 



Big Creek and Cox Pup 

Birch Creek 

Glacier Creek 

Greenstone Creek 

Midnight Creek 

Do 

Short Creek 

Straight 

Fifth of July Creek 

District total 



32 



NAp 



To 1 962 
1917-36 
To 1962 
1940-42 
1917-18 
1940-42 

1918 
1916-20 

1922 
1916-72 



2,100 
5,000 

150 

300 

537 (Sn metal) 
7,320 

© 

( 3 ) 

s300 (Sn metal) 
=402,100 (Sn metal) 



NAp Not Applicable U Unknown 

1 Totals calculated assuming concentrates contained 75 pet Sn, except for Tofty tin belt concentrates (See footnote 4. 

2 Several thousand pounds concentrate 

; Cassitente recovered, quantity unknown 

4 Total calculation based on 60-pct reported average tin content of concentrate ( 10). 

5 Few thousand pounds tin metal 



13-14 

14 
13-14 

14 

13-14 

13 

14 

NAp 



CIRCLE DISTRICT 


Deadwood and Boulder Creeks 


33 


To 1982 


( 3 ) 


15-17 


MELOZITNA DISTRICT 


Mason Creek 


30 

29 

29 

NAp 


1918 
1938-43 

1983 
1918-83 


2,000 

=500 (Sn metal) 
= 12,500 (Sn metal) 
s14,500 (Sn metal) 


14 


Tozimoran Creek 


18 


Do 


12 


District total 


NAp 


STATEWIDE 


Total for Alaska 


NAp 


1901-83 


=5,830,600 (Sn metal) 


NAp 



about 0.2 pet of the 1983 U.S. consumption of primary tin 
(88.000.000 lb) (20). 

Published lode- and placer-tin reserve estimates are 
summanzed in table 2. The largest reserves are at the Lost 
River Mine (map location 13) on the western Seward 
Peninsula, where indicated tin reserves are estimated at 
85.000.000 lb in a zone of 0.15 pet Sn. 5,200,000 lb in a 
deposit grading 0.26 pet Sn, and 1,600,000 lb in a deposit 
grading 1.3 pet Sn. Inferred reserves at Lost River total 
21 .000.000 lb of tin in four deposits ranging in grade from 0.4 
to 1 .5 pet Sn. Approximately 20.000.000 lb Sn is also inferred 
at the Coal Creek prospect in the Chulitna area (map location 
49) and approximately 300.000 and 1,000,000 lb Sn are 
reported to be indicated and inferred, respectively, at the 
Boulder Creek prospect (map location 51) in the southern 
Alaska Range' (24-25). Tofty (map location 36) is the only 
placer area for which tin reserve figures have been 
published. Approximately 3.900,000 lb Sn are indicated to 



Table 2. — Tin reserves in Alaskan lode and placer deposits 
(Published estimates) 



Deposit name 



Map 
location 
(fig 1) 



Grade, 
pet 



Reserves, million lb 



Measured 
and indicated 



Inferred 



References 



' Reed (27-2ffi suggests substantially lower reserves at Boulder Creek 



Lode deposits: , 












Lost River Mine: 












Cupola 




0.151 


85 


NR 


21 


Cassitente Dike . . 




1.5 


NR 


2.4 




Do 


13 


1.3 


1.6 


NR 




Do 


'>1.0 


NR 


9 


22 


Do 




.4 


NR 


5.2 


Do 




26 


5.2 


NR 




Ida Bell Dike 




.76 


NR 


4.4 




Coal Creek 


49 


2 


NR 


20 ' 


24 


Boulder Creek ] 

Do j 


51 


'2.41 
2.41 


NR 
3 


1.0 1 
NR 


25 


Placer deposits: 












Tofty 

Do 

Cape Creek 


36 | 
12 


2 2.63 


3.9 


NR 


11, 19, 26 


2 0.58 


NR 


.7 


26 


2 2.6 


NR 


2.2 


23 


Total 






960 


44.9 


NAp 










NAp Not applicable. 


'Gr< 


ide uncertain 








NR None reported. 


2 Po 


jnds per cubic yard. 







remain in 1 ,490,000 yd 3 of placer deposits, and approximate- 
ly 733,000 lb Sn are inferred to remain in 1 ,259,000 yd 3 of 
tailings gravels in the Tofty area 8 (11, 19, 26). 

Additional reserves can be calculated from figures given 
by Mulligan (23). Calculations suggest that 2,200,000 lb Sn 
remain in 850,000 yd 3 gravel at Cape Creek in the Cape 
Mountain area (map location 12). Also, based on minimal drill 
data, in excess of 400,000 lb Sn is suggested to occur in the 
combined placer deposits of Ear Mountain and Tozimoran 
and Morelock Creeks (map locations 10, 29, and 31) ( 14, 29). 



TANTALUM AND COLUMBIUM 

Tantalum and columbium have no reported production in 
Alaska, and no domestic production has been reported since 
1959 (30-31). The only established reserves of columbium in 
Alaska are at Tofty (map location 36), where approximately 
135,000 lb of columbium oxide are inferred to be contained 
within 2,660,000 yd 3 of placer and tailings gravels (32). 



BUREAU OF MINES INVESTIGATIONS 



The Bureau has published several reports concerning 
tin, tantalum, or columbium in Alaska. Recent work includes 
published and ongoing studies in the Sithylemenkat (33-34), 
Porcupine Plateau (35-36), Tofty (32), and Circle Quadrangle 
areas of interior Alaska ( 16, 37-38), the Mt. McKinley and Lake 
Clark areas of the central and southern Alaska Range 
(39-40), and the Selawik Hills area of northwestern Alaska 
(41 ). Previous Bureau studies include extensive evaluation of 
placer and lode deposits on the western Seward Peninsula 
(23, 29, 42-47) as well as investigations in the Manley Hot 
Springs district (11) and Melozitna district (18) in interior 
Alaska. 



TRENDS OF ALASKAN TIN OCCURRENCES 

Alaskan lode and placer occurrences containing tin, 
tantalum, and/or columbium are listed in the appendix, in 
tables A-1 and A-2. Where available, abbreviated geologic, 
geochemical, and production data are provided. Generally, 
the criteria for inclusion of a tin occurrence or deposit in these 
tables were (1 ) the presence of greater than trace amounts of 
tin and (2) a possibility for large, although undefined, 
volumes of material. However, a few tin occurrences that are 
in unique geologic settings but do not necessarily meet these 
criteria are also included for illustrative purposes. All 
reported occurrences of tantalum and/or columbium are 
included in these tables. The only commodities listed are 
metals with potential economic importance. 

On a broad scale, the tin-bearing lode and placer 
occurrences of Alaska are part of a belt of tin mineralization 
that extends along the western flank of North and South 
America. As shown in figure 1 (map), the Alaskan portion of 
the belt parallels major geologic provinces from the 
Alaska-Yukon border across central Alaska to the Seward 
Peninsula (48). Most of the tin occurrences within this belt 
are spatially associated with nearby outcropping or subcrop- 
ping biotite-bearing composite intrusions or felsic hypabyssal 
stocks and dikes of Cretaceous or early Tertiary age. The 
intrusions cut rocks of Precambrian (?) to Tertiary age and 
probably resulted from anatectic melting of sialic crust during 
a postorogenic period of magmatism (48-50). Thus, the 
distribution of tin occurrences in Alaska may be an indirect 
indication of areas underlain by continental crust. 

On a smaller scale, the Alaskan tin belt is composed of 
several stanniferous trends, each of which has particular 
geologic characteristics and a variety of mineral deposit 
types. In figure 1, these trends are referred to as "Alaska 
Range," "Kuskokwim," "Yukon-Tanana," "Kokrine-Hodzana," 
"Seward Peninsula," "Brooks Range," and "Northeast Alas- 
ka." These mineral trends generally coincide with trends of 
granitic intrusions and gravity lows (51-52) and generally 
correlate with areas underlain by miogeosynclinal shelf or 



8 Thomas ( 1 1) estimates 733,000 lb Sn in gravels in the Tofty area with a 
total volume of 1 ,259,000 yd 3 , but does not give specific reserve locations. 
Wayland (19), however, estimates 433,600 lb Sn in three specific tailings 
areas, but does not give specific locations of in-place placer tin reserves. 



slope deposits. Parallelism with the trend of some ophiolite 
terranes and regional fault zones also suggests that the tin 
trends are in part controlled by crustal suture or major 
deep-seated fracture zones. Each of the regional trends is 
discussed below. 



ALASKA RANGE 

The Alaska Range trend of tin occurrences (fig. 1) 
extends south from near Healy to near Lake Clark, generally 
subparallel to the McKinley strand of the Denali fault. The 
trend includes the Chulitna-Yentna and parts of the Dall and 
Kantishna mineral belts delineated by Hawley (39). Sulfide- 
rich veins and skarns are locally enriched in tin, and 
cassiterite is present in greisenized granite stocks along this 
trend. A volcanogenic massive sulfide deposit in the 
northeastern part of the trend contains local tin enrichments. 
All the tin occurrences, except the massive sulfide, show 
close affinities to approximately 56-m.y.-old McKinley Series 
biotite-muscovite granites (49, 53) that generally intruded 
Jurassic to Cretaceous age argillite south of the Denali fault, 
but which also cut mixed volcano-sedimentary assemblages 
west of Cantwell and north of the Denali fault. 



YUKON-TANANA 

The Yukon-Tanana trend of tin occurrences follows the 
Yukon-Tanana Upland province in interior Alaska and 
generally parallels the Tintina fault to the north, which is 
interpreted as an extension of the Rocky Mountain trench in 
Canada (54). Virtually every placer gold district in the 
province contains at least traces of cassiterite, but most of 
the tin occurrences are confined to the area between Circle 
Hot Springs and the White Mountains, north and northeast of 
Fairbanks (fig. 1 ). Tin occurrences in this area are associated 
with late Cretaceous-early Tertiary age biotite granite 
composite intrusions that have intruded the sedimentary 
facies boundary between late Precambrian-early Paleozoic 
miogeosynclinal shelf and slope deposits, a boundary 
represented by the transition between rocks of the Wicker- 
sham and White Mountain terranes to the northwest and the 
Yukon-Tanana terrane to the southeast (54-55). This 
boundary may be the fault-offset analog of the MacKenzie 
Mountain-Selwyn Basin transition in Canada (54, 56-57), 
which coincides with a belt of Canadian tin occurrences (58). 
The Yukon-Tanana tin trend, therefore, may be an extension 
of the Canadian tin belt. 

The placer tin deposits of the Tofty area in the Manley Hot 
Springs district have similarities to and may be transitional 
between tin occurrences of the Yukon-Tanana and Kuskok- 
wim tin trends. At Tofty, although the tin source is unknown, 
both a biotite granite, similar to those of the Yukon-Tanana 
trend, and a monzonite stock, similar to those of the 
Kuskoskwim trend, are exposed (19). Like the placer 
deposits of the Yukon-Tanana trend, the tin at Tofty occurs 
as an accesory to gold; however, like many of the Kuskokwim 



trend deposits, the Tofty deposits are enriched with 
columbium. Lastly, both the Tofty and the Kuskokwim trend 
deposits are underlain by clastic sedimentary rocks of 
Jurassic-Cretaceous or Cretaceous age (19). 



KUSKOKWIM 

The Kuskokwim trend of tin occurrences extends 
subparallel to the Iditarod-Nixon Fork fault in west-central 
Alaska, from near Aniak northeastward to near Manley Hot 
Springs (fig. 1). Tin occurrences are associated with a varied 
assemblage of hypabyssal and plutonic intrusive rocks of 
monzonitic to granitic or rhyolitic composition. These rocks 
are of late Cretaceous to early Tertiary age and generally 
intrude sedimentary rocks of the Cretaceous Kuskokwim 
group. The presence of hypabyssal stocks and dikes, locally 
widespread thermal alternation and tourmalinization, and 
tin-silver-copper-rich veins (59) (table A-1) suggests that 
many of the occurrences in this area occur within shallow, 
possibly subvolcanic settings. 



KOKRINE-HODZANA 

The Kokhne-Hodzana tin trend lies northwest of the 
Kuskokwim and Yukon-Tanana trends, stretching from near 
Tanana northeastward across interior Alaska subparallel with 
the Kaltag fault system (fig. 1). Tin occurrences along the 
trend are associated with a 90- to 110-m.y.-old suite of 
plutons that has intruded lower to middle Paleozoic (?) age 
pelitic metasedimentary rocks of the Ruby "geanticline" (50, 
60-62). These intrusions are in part separated from younger 
ones in the Yukon-Tanana and Kuskokwim trends by the 
southwest-trending Kaltag fault. The Ruby district (map 
location 32) may be an extension of the Kokrine-Hodzana 
trend that has been offset to the southwest by the Kaltag 
fault. 



SEWARD PENINSULA 

The Seward Peninsula tin trend largely consists of a 
group of deposits that extends across the Seward Peninsula 
from Cape Mountain eastward to Kougarok Mountain and 
beyond (fig. 1). The deposits are characterized by tin- 
fluorine-beryllium zoned replacement lodes and veins formed 
by metasomatism of upper Precambrian (?) to middle 
Paleozoic age pelitic and carbonate rocks adjacent to 70- to 
80-m.y.-old biotite-bearing granites (table A-1). 

Additional tin occurrences, associated with the 80-m.y.- 
old Darby pluton, have been identified in the Darby Mountain 
area of the southeastern Seward Peninsula (63). Tin 
occurrences in this area are probably unrelated geologically 
to the other Seward Peninsula occurrences. 



NORTHEAST ALASKA AND BROOKS RANGE 

Unlike other tin occurrences in Alaska, tin occurrences 
of the northeast Alaska trend (fig. 1) are associated with 
probable middle Paleozoic age (350 m.y.) intrusions. These 
intrusions have invaded Precambrian (?) to lower Paleozoic 
age miogeosynclinal metasedimentary rocks of the Porcu- 
pine Plateau (36). The northeast Alaska trend may extend 
into the Brooks Range trend (fig. 1), where recent 
interpretations (64) suggest intrusions of similar mid- 
Paleozoic age; however, detailed data are lacking. 



OTHER AREAS WITH TIN OCCURRENCES 

Several tin occurrences in southern and southeast 
Alaska are not associated with known tin trends. (See figure 
1 and "Other Occurrences" portion of table A-1 .) In southern 
Alaska, near Cordova, tin is associated with two breccia or 
altered zones in greenstone and metasedimentary rocks. In 
southeast Alaska, tin occurs as a minor element in several 
base-metal vein or replacement deposits. 



TIN LODE OCCURRENCES 



Lode occurrences of tin in Alaska generally are of five 
main types: greisen. vein, skarn. pegmatite, and volcanogenic 
massive sulfide. Tin also occurs in a fumarole 
deposit at the Valley of Ten Thousand Smokes (65) (map 
location 54). Greisen and vein occurrences far outnumber 
the other types of occurrences; however, in terms of 
production, the skarn type (at the Lost River Mine, map 
location 13) historically has been most important. The 
following sections summarize the tin lode occurrence data 
presented in table A-1. 



GREISEN 

Greisen occurrences are centered about or confined to 
biotite granite or felsic hypabyssal stocks. These occurrences 
are typified by lithophile element-rich alteration 
minerals that accompany disseminated and stockwork or 
sheeted vein mineralization within or near the cupola of an 
intrusion. Important examples include the Lost River Mine 
(map location 13) and the recent discovery at Coal Creek in 
the Chulitna area (map location 49). Other unevaluated 
occurrences include greisen mineralization at Lime Peak 
(map location 34). Ketchem Dome in the Circle mining district 
(map location 33). Sithylemenkat (map location 25). Kougar- 
ok Mountain (map location 16). Rapid River (map location 3). 
Esotuk and McCall Glaciers (map location 1), and Ohio 
Creek in the Chulitna area (map location 49). 



VEIN 

Vein mineralization most commonly occurs distal from 
the intrusion. The veins cut regionally or contact metamor- 
phosed rocks and typically can be traced for hundreds of feet. 
Mineralization is usually polymetallic and silver- and sulfur- 
rich; and it is usually enclosed within a shear or breccia zone 
by a relatively restricted quartz-rich alteration selvage. Unlike 
the stockwork and sheeted veins associated with greisen 
mineralization, these veins are generally more continuous, 
more enriched in silver and sulfur, and usually are relatively 
isolated. 

Examples of Alaskan vein occurrences include the 
Boulder Creek prospect (map location 51), which is 
described as a cluster of narrow, open-space-filling fractures 
localized along a 1- to 6-m-wide fracture zone within 
metasedimentary rocks overlying a granite cusp (28). Lesser 
known occurrences that may prove to be important include 
those at Cosna (map location 37), Quartz Creek (map 
location 28), the Omilak and Foster prospects (map location 
21), and new discoveries in the western Medfra Quadrangle 
(Win and Won prospects, map locations 38-39). 



SKARN 

Tin-bearing skarn deposits occur as tabular or vein like 
zones within carbonate rocks adjacent to biotite granites or 



felsic dikes. Commonly, like the adjacent greisenized granite, 
these deposits contain lithophile element-rich alteration 
minerals and potentially economic concentrations of fluorine, 
beryllium, and tungsten. Well-known metasomatic- 
replacement deposits are the Lost River Mine (map location 
13) and Cape Mountain lode (map location 12). Minor 
tin-bearing skarn occurrences also occur at Mountain Creek 
(Rapid and Porcupine Rivers area, map location 3) in 
northeastern Alaska and several prospects in the Brooks 
Range (Kaluich and two unnamed occurrences, map 
locations 4-6). 



PEGMATITE 

Tin-bearing pegmatites are poorly documented in 



Alaska. Pegmatites carrying tin values have been found at 
the Ketchem Dome prospect in the Circle district (map 
location 33), at the Janiksela occurrence in the Fairbanks 
district (map location 35), and at the Kiana occurrence (map 
location 7) in the Brooks Range. 



VOLCANOGENIC 
MASSIVE SULFIDE 

Tin-bearing volcanogenic massive sulfide has been 
discovered at the Sheep Creek prospect (map location 47) in 
the central Alaska Range (66). One 350-ft drill intersection 
there averages 0.035 pet Sn. A narrower, 8-ft zone contains 
1 .2 pet Sn. The deposit is hosted within a siliceous exhalite 
(?) horizon and overlain by graphitic schists. 



TIN PLACER OCCURRENCES 



Like most world tin production, the bulk of Alaskan tin 
production comes from placer deposits. Cassiterite is a 
common accessory mineral in placer concentrates through- 
out much of Alaska. Approximately 90 pet of Alaskan placer 
production has been from the western Seward Peninsula. 
The remainder was recovered with gold from placer mines in 
interior Alaska (tables 1 and A-2). Placer tin occurrences of 
unknown grade occur in the Sithylemenkat River area (map 
location 25) of interior Alaska and in the Rapid and Porcupine 
Rivers area (map location 3) of northeastern Alaska (33-35). 
Anomalously large amounts of tin also have been found in 
numerous creeks in other areas of the Seward Peninsula, in 
interior Alaska, and in the Yentna district (map location 52), 
southeast of the Alaska Range (67). 

Tin occurs as cassiterite, along with various other 
high-specific-gravity minerals such as gold, scheelite, wolfra- 
mite, magnetite, ilmenite, rutile, garnet, monazite, allanite, 
zircon, columbite, and cinnabar, in the heavy-mineral fraction 
of sands and gravels. Many of the tin placer deposits listed in 
table A-2 contain associated gold, tungsten, rare-earth 
elements, tantalum, and/or columbium, which must be 
considered in evaluating the placer's economic viability. 

Cassiterite occurs in placers both as individual grains, 
which range from extremely fine to sand and pebble size, and 
as a constituent of larger cobbles. Grains of all sizes may 
vary from extremely angular to well-rounded. Cassiterite- 



bearing cobbles, sometimes termed "tinstone," often were 
not recovered in the past because their size necessitated 
hand sorting. 

Cassiterite is present in bench, stream, river, and beach 
placers. Small, but anomalous amounts of cassiterite have 
also been detected in bottom sediment samples collected 
offshore in the Bering Strait-Cape Prince of Wales area (68), 
suggesting a potential for marine placers. 

Insufficient data preclude determining average grade 
and yardage figures for tin-bearing placer deposits in 
Alaska as a whole. Generally, however, creeks that have 
yielded tin contain approximately 1 lb/yd 3 cassiterite or more, 
60 pet or more tin in concentrates, and 10,000 yd 3 or more of 
placer material (table A-2). However, the major tin-producing 
creeks, including Buck, Grouse, and Cape Creeks in the 
Potato and Cape Mountain areas (map locations 11-12) on 
the Seward Peninsula and many of the creeks in the Tofty 
area (map location 36), probably contain material grading 
greater than 2.0 lb/yd 3 Sn. On Buck and Grouse Creeks, 
2,204,600 lb Sn was produced from 560,000 yd 3 of gravels 
between 1901 and 1964 (42-43). In the Tofty area, 
approximately 1,490,000 yd 3 of reserve placer gravels is 
indicated to contain 2.6 lb/yd 3 Sn (19). A published drill report 
on Cape Creek indicates approximately 850,000 yd 3 of 
gravels with an average grade of 2.6 lb/yd 3 Sn (23). 



REGIONAL FEATURES OF ALASKAN 
TANTALUM AND COLUMBIUM OCCURRENCES 



Worldwide, deposits of columbium and tantalum occur in 
carbonatite-alkaline syenite complexes, pegmatites, or alkali- 
rich granites (69). Until 1961 , the major source of columbium 
consumed in the United States was columbite in placers 
derived from the erosion of peralkaline granites and 
pegmatites in Nigeria; however, the major source today is 
pyrochlore obtained from carbonatites in Canada and Bolivia. 
Pegmatites are the dominant source of tantalum in the world. 

In Alaska, most of the columbium and tantalum 
occurrences are found within the same trends as the tin 
occurrences. Columbium and tantalum are reported in the 
Northeast Alaska, Kokrine-Hodzana, Yukon-Tanana, and 
Kuskokwim tin trends. Where they are associated with tin, 



tantalum and columbium occur within minor accessory 
minerals either within the tin-bearing granite or within a 
related, more alkaline phase of the granite. Columbium and 
tantalum may also occur in trace amounts in cassiterite or 
may be associated with cassiterite in pegmatites. 

In other areas of Alaska, for example southeastern 
Alaska and the western Yukon-Koyukuk basin, tantalum and 
columbium occurrences are not associated with tin and do 
not occur within tin trends. In these areas, columbium and 
tantalum are associated with peralkaline intrusions or 
pegmatites. Other alkaline intrusive complexes in southeast- 
ern, western, and other areas of Alaska may also contain 
columbium and tantalum. 



TANTALUM AND COLUMBIUM LODE OCCURRENCES 



Tantalum and columbium reported in Alaskan lode 
prospects occur in trace amounts associated with uranifer- 



ous alkaline complexes, in pegmatites, in tungsten-bearing 
molybdenum porphyries or in tin-bearing greisens (table 



A-1). Tantalum and columbium in these occurrences may be 
recoverable as byproduct commodities. 

At Bokan Mountain (map location 61), columbium occurs 
in grades of 0.01 to 1.0 pet and is associated with uranium 
and thorium minerals within a peralkaline granite (70). 
Mineralization in the Bokan Mountain area consists of 
disseminated uranium-thorium minerals in granite, aplite, 
and pegmatite: hydrothermally deposited uranium-thorium 
minerals in or near fractures; and uranium-thorium minerals 
in interstices of quartzite (70-71). Both columbite and 
pyrochlore have been identified. 

In the Selawik Hills (map location 9). columbium is found 
in uraniferous altered zones within an alkaline complex (41). 
A columbium-uranium-titanium-bearing mineral has been 
identified in this area. This same or a similar mineral has 
been reported in the placers of Vulcan and Clear Creeks 
(map location 22). where it is apparently derived from the 
Darby Mountain igneous complex in the eastern Seward 
Peninsula. 



Columbium occurs in a pegmatite at the Edelweiss 
prospect (map location 59) in southeastern Alaska, and 
tantalum and columbium are reported in a pegmatite at the 
Kiana occurrence (map location 7) in the western Brooks 
Range (72-73). At the Kiana occurrence, columbite and 
tantalite are reported to occur with cassiterite. Both localities 
remain unevaluated. 

An open-ended 4,000-ft-long by 200- to 2,000-ft-wide 
columbium soil geochemical anomaly with values of 0.006 to 
0.018 pet Cb corresponds to molybdenum-tungsten miner- 
alization associated with an altered porphyry at Bear 
Mountain (map location 2) in northeastern Alaska (74). 
Pyrochlore was identified in a pan concentrate sample 
collected nearby. 

At the Kougarok prospect (map location 16) on the 
Seward Peninsula, tantalum and columbium values in the 
0.01- to 0.03-pct range are associated with parts of the 
tin-mineralized greisen. The tantalum- and columbium- 
bearing minerals have not been identified. 



COLUMBIUM AND TANTALUM PLACER OCCURRENCES 



Columbium and, less commonly, tantalum occur in 
anomalously large amounts in many placer and heavy- 
mineral concentrate samples in Alaska. They are not known 
to occur in concentrations that would justify mining them as a 
primary commodity, but some of the higher concentrations 
may be recoverable as byproducts of tin or gold mining. The 
only occurrences that have been studied in any detail are at 
Tofty (map location 36) in the Manley Hot Springs district of 
interior Alaska. (See table A-2 for detailed data on placer 
occurrences.) 

At Tofty. columbium occurs within columbite and 
possibly aeschynite [Ce, Ca, Fe. Th)(Ti, Cb) ? (0, OH) 6 ] (32). 
The columbium occurs in grades averaging 0.05 lb/yd 3 
columbium oxide and is associated with tin and gold in the 
placer deposits; however, the columbium and tin may have 
different sources. The sources of the columbium and tin are 
unknown. 

Also in interior Alaska, anomalously large amounts of 
tantalum and columbium occur in the Sithylemenkat area 
(map location 25). where placer concentrate samples 
containing detectable columbium and tantalum average 0.26 
and 0.062 pet. respectively (34). Several other placer 
deposits in interior Alaska, including those of the Ruby, 
Circle, and Fairbanks districts (map locations 32-33 and 35), 
also contain anomalously large amounts of columbium (75). 

In northeastern Alaska, values of 0.05 to 0.1 pet Cb have 
been found in association with tin, tungsten, and rare-earth 



metals in sluice-box concentrate samples from the Rapid 
River drainage (map location 3) (35). At the Bear Mountain 
prospect (map location 2), concentrate from a bulk sample of 
alluvial gravel collected 2 mi downstream from the mineral- 
ized zone contained 0.15 pet Cb and 3 pet W (74). 

On the Seward Peninsula, columbium is reported in 
tin-bearing gravels of Tuttle Creek (Ear Mountain area, map 
location 10), Boulder and Cape Creeks (Cape Mountain 
area, map location 12), and Cassiterite Creek (Lost River 
Mine area, map location 13) (28, 42, 75). Reported values 
range from 0.001 to 0.10 pet Cb in spectrographic analyses 
of churn-drill concentrate samples. Columbium values 
associated with uranium occur in the Clear and Vulcan 
Creeks area (map location 22) of the Darby Mountains on the 
southeastern Seward Peninsula, where a range of 0.03 to 
0.18 lb/yd 3 Cb and an average of 1 pet Cb in concentrates (19 
samples) was reported (44). Creeks draining the Kougarok 
Mountain (map location 16) and Granite Mountain (map 
location 23) areas on the central and eastern Seward 
Peninsula, respectively, are also reported to contain anoma- 
lously large concentrations of columbium (75). 

In the Kuskokwim Mountains, anomalously large 
amounts of columbium are reported in stream gravels from 
the Vinasale Mountain (map location 42) and Marvel Creek 
(map location 46) areas (75). These occurrences have not 
been evaluated. 



SUMMARY 



Data compiled from published and unpublished sources 
indicate that Alaska contains a significant portion of the 
United States reserves of tin. The State also contains minor 
reserves of columbium and occurrences of tantalum. All 
three of these critical and strategic metals could be obtained 
from Alaska during a period of national shortage. 

An estimated 5.830.600 lb of tin has been produced, and 
an estimated additional 140,900.000 lb has been measured, 
indicated, or inferred to occur within Alaskan lode and placer 
deposits Alaskan tin reserves represented about 150 pet of 
U.S. consumption of primary tin in 1983. whereas the State's 
current production of about 200,000 lb yr represents about 
0.2 pet of domestic consumption. Western Seward Peninsula 
placer mines have yielded most of the tin produced; however, 
it is that area s lode deposits that contain most of the State's 
reserves. 



On a broad scale, Alaskan tin lode and placer 
occurrences are part of a belt of tin mineralization that 
extends along the western flank of North and South America. 
On a smaller scale, however, the Alaskan portion of the "tin 
belt" comprises several stanniferous trends, each with 
particular geologic attributes and a variety of lode and placer 
occurrence types. Five main tin lode types are represented: 
greiaen, vein, skarn, pegmatite, and volcanogenic massive 
sulfide. Although greisen and vein occurrences are the most 
abundant in the State, skarn deposits have historically been 
the most valuable. Bench, stream, river, and beach placers 
are also represented within the Alaskan tin trends. Most of 
these placers are located on the Seward Peninsula or in 
interior Alaska; however, occurrences are also reported in 
northern and south-central Alaska. 

Alaska has not produced columbium or tantalum and 



has no tantalum reserves. Approximately 135,000 lb of 
niobium oxide is inferred within the tin- and gold-bearing 
placers of Tofty, in interior Alaska. Anomalously high 
columbium concentrations are also reported in association 
with uraniferous alkaline complexes in southeastern and 
western Alaska, with a molybdenum-tungsten-mineralized 
porphyry in northeastern Alaska, and in tin- and/or gold- 
bearing placers on the Seward Peninsula and in interior 



Alaska. Anomalously high tantalum and columbium values 
are reported in association with tin-bearing greisen on the 
Seward Peninsula, with pegmatites in southeastern and 
northern Alaska, and in a placer in interior Alaska. Where the 
columbium and tantalum concentrations are relatively high, 
these minerals may be recoverable as byproducts of tin or 
gold mining. 



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Tectonic and Economic Significance of Late Devonian and Late 
Proterozoic U-Pb Zircon Ages From the Brooks Range, Alaska. AK 
Div. Geol. and Geophys. Surv. Geol. Rep. 61. 1979. dd. 36-41. 

65. Lovenng. T. S. Halogen and Acid Alteration at Fumarole No. 
1. Valley of Ten Thousand Smokes, Alaska. Geol. Soc. America 
Bull., v. 68. 1957. pp. 1585-1603. 

66. Hammit. J. (Bear Creek Min. Co.). Private communication. 
1984: available upon request from J. D. Warner, BuMines, 
Fairbanks. AK. 

67 Caps. S. R. The Yenta District. Alaska. U.S. Geol. Surv. Bull. 
534. 1913. 75 pp. 

68. Larson. B. R.. C H. Nelson. C. Heropoulos, and J. J. 
Patry Distribution of Trace Elements in Bottom Sediment of the 
Northern Bering Sea. U.S. Geol. Surv. OF 80-399. 1980, 40 pp. 

69. Dawson. K. R. Niobium (Columbium) and Tantalum in 
Canada. Geol. Surv Can. Econ. Geol. Rep. 29. 1974. 157 pp. 

70. MacKevett. E. M . Jr. Geology and Ore Deposits of the Bokan 
Mountain Uranium-Thorium Area. U.S. Geol. Surv. Bull. 1 154, 1963, 
82 pp 

71. Staatz. M. H. I and L Uranium and Thorium Vein Systems. 
Bokan Mountain. Southeastern Alaska. Econ. Geol. v. 73. No. 4. 
1978. pp. 512- 524 

72 Anderson. E. Mineral Occurrences in Northwestern Alaska. 
AK Dept Mines Pamphlet 5-R. 1944, 37 pp 

73 Lathram. E. H.. J. S Pomeroy. H S Berg, and R. A Loney. 
Reconnaissance Geology of Admiralty Island, Alaska. U.S. Geol. 
Surv Bull. 1181-R. 1965. 48 pp. 

74 Barker. J C . and R. C. Swambank. A Tungsten-Rich 
Molybdenum Porphyry Occurrence at Bear Mountain, Northeastern 
Alaska BuMines OFR 85-5. 1984. 64 pp. 

75. Samsbury. C L.. and B I Thomas Location of Anomalous 
Concentrations of Metals in Alaskan Placer Concentrate Samples. 
(Maps j BuMines OFR 56-76. 1975 

76. Grybeck. D Known Mineral Deposits of the Brooks Range, 
Alaska. US. Geol Surv. OF 77-166-C. 1977. 45 pp. 

77 Brosge . W. P. and H N Reiser. Preliminary Geologic and 
Mineral Resource Maps (Excluding Petroleum). Arctic National 
Wildlife Range. Alaska US Geol. Surv. Map of 76-539, 1976. 

78 Garland. R. E . G E Eakins. T C Trible. and W. W. 



McClintock. Geochemical Analysis of Rock and Stream Sediment 
Samples, Survey Pass A-4, A-5, A-6, B-5, and B-6 Quadrangles, 
Alaska. AK Div. Geol. and Geophys. Surv. Open File Rep. 67, 1975, 
2 pp. 

79. Dillion, W. S., M. A. Moorman, and L. Lueck. Geochemical 
Reconnaissance of the Southwest Wiseman Quadrangle, Summary 
of Data on Rock Samples. AK Div. Geol. and Geophys. Surv. Open 
File Rep. 133B. 1981, pp. 67-68, 80, 96. 

80. U.S. Bureau of Mines. A Mineral Appraisal of the Areas 
Traversed by the Salmon and Noatak Rivers in the Western Brooks 
Range: A Summary Report. BuMines OFR 50-79, 1979, 16 pp. 

81. Borg, H. C, and E. H. Cobb. Metalliferous Lode Deposits of 
Alaska. U.S. Geol. Surv. Bull. 1246, 1967, 254 pp. 

82. Lu, C. J., L. E. Heiner, and D. P. Harris. Known and Potential 
Ore Reserves, Seward Peninsula, Alaska. Univ. AK, Fairbanks, AK, 
Miner. Ind. Res. Lab. Rep. 18, 1968, 105 pp. 

83. Sainsbury, C. L., and Hamilton, J. C. Mineralized Veins at 
Black Mountain, Western Seward Peninsula, Alaska. U.S. Geol. 
Surv. Prof. Paper 575-B, 1967, pp. B21-B25. 

84. Sainsbury, C. L., R. Kachadoohan, T. E. Smith, and W. C. 
Todd. Cassiterite in Gold Placers at Humboldt Creek Serpentine- 
Kougarok Area, Seward Peninsula, Alaska. U.S. Geol. Surv. Circ. 
565, 1968, 7 pp. 

85. Puchner, C. C. (Anaconda Miner. Co.). Private communica- 
tion, 1984; available from J. D. Warner, BuMines, Fairbanks, AK. 

86. Mulligan, J. J. Lead-Silver Deposits in the Omilak Area, 
Seward Peninsula, Alaska. BuMines Rl 6018, 1962, 44 pp. 

87. Miller, T. P., and R. L. Elliot. Metalliferous Deposits Near 
Granite Mountain, Eastern Seward Peninsula, Alaska. U.S. Geol. 
Surv. Circ. 614, 1969, 19 pp. 

88. Freeman, L. (Resource Associates of Alaska, Inc.). Private 
communication, 1983; available upon request from J. D. Warner, 
BuMines, Fairbanks, AK. 

89. Barker, J. C. (BuMines). Private communication (to J. J. 
Mulligan), 1983; available upon request from J. D. Warner, BuMines, 
Fairbanks. AK. 

90. Thomas, B. I. (BuMines). Private communication (to R. V. 
Berryhill), 1964; available upon request from J. D. Warner, BuMines, 
Fairbanks, AK. 

91. Chapman, R. M. Geochemical Anomalies in Bedrock, West 
Half of Kantishna River Quadrangle. Ch. in Accomplishments During 
1976. U.S. Geol. Surv. Circ. 751 -B, 1976, pp. B35-B36. 

92. Pilcher, S. H. (Duval Corp.). Private communication, 1984; 
available upon request from J. D. Warner, BuMines, Fairbanks, AK. 

93. Bundtzen, T. K., and G. M. Laird. Geologic Map of the Iditarod 
D-2 and Eastern D-3 Quadrangles, Alaska. AK Div. Geol. and 
Geophys. Surv. Geol. Rep. 72, 1982. 

94. Cady, W. M., R. E. Wallace, J. M. Hoare, and E. S. Webber. 
The Central Kuskokwim Region, Alaska. U.S. Geol. Surv. Prof. 
Paper 268, 1955, 132 pp. 

95. West, W. S. Reconnaissance for Radioactive Deposits in the 
Lower Yukon-Kuskokwim Region, Alaska, 1952. U.S. Geol. Surv. 
Circ. 328, 1954, 10 pp. 

96. Maddren, A. G. Gold Placers of the Lower Kuskokwim, With a 
Note on Copper in the Russian Mountains. U.S. Geol. Survey Bull. 
622, 1915, pp. 292-360. 

97. Bundtzen, T. K. Geology and Mineral Deposits of the 
Kantishna Hills, Mt. McKinley Quadrangle, Alaska. M.S. Thesis, 
Univ. AK, Fairbanks, AK, 1981, 238 pp. 

98. Hawley, C. C, and A. L. Clark. Geology and Mineral Deposits 
of the Chulitna-Yentna Mineral Belt, Alaska. U.S. Geol. Surv. Prof. 
Paper 758-A, 1973, 10 pp. 

99. Geology and Mineral Deposits of the 

Upper Chulitna District, Alaska. U.S. Geol. Surv. Prof. Paper 758-B, 
1974, 47 pp. 

100 Cobb, E. H. Summary of References to Mineral Occurrences 
(Other Than Mineral Fuels and Construction Materials) in the Healy 
Quadrangle, Alaska. U.S. Geol. Surv. OF 78-1062, 1978, 112 

PP- 

101. Reed, B L. Disseminated Tin Occurrences Near Coal Creek, 
Talkeetna Mountain D-6 Quadrangle, Alaska. U.S. Geol. Surv. OF 
78-77, 1978, 8 pp. 

102. Cobb E. H., and B. L. Reed. Summaries of Data on and Lists 
of References to Metallic and Selected Nonmetallic Mineral Deposits 
in the Talkeetna Quadrangle, Alaska. U.S. Geol. Surv. OF 80-884, 
1980. 106 pp. 

103 Maloney, R. P., and B. I. Thomas. Investigation of the 
Purkeypile Prospects, Kuskokwim River Basin, Alaska. BuMines 
OFR 5-66, 1966, 12 pp. 

104. Fechner, S. (BuMines). Private communication, 1983; 
available upon request from J. D. Warner, BuMines, Fairbanks, AK. 

105. Brew, D. A., B. R. Johnson, D. Grybeck, A. Griscom, D. F. 
Barnes, A. L. Kimball, J. C. Still, and J. L. Rataj. Mineral Resources 



10 



of the Glacier Bay National Monument Wilderness Study Area, 
Alaska. U.S. Geol. Surv. OF 78-494, 1978, 656 pp. 

106. Karl, S. M. Preliminary Map and Tables Describing 
Metalliferous and Selected Nonmetalliferous Mineral Deposits in the 
Petersburg and Eastern Port Alexander Quadrangles, Alaska. U.S. 
Geol. Surv. OF 80-793, 1980. 

107. Eakins, G. R. Uranium Investigations in Southeastern 
Alaska. AK Div. Geol. and Geophys. Surv., Geol. Rep. 44, 1975, 62 
pp. 

1 08. Cobb, E. H. Summary of References to Mineral Occurrences 
(Other Than Mineral Fuels and Construction Materials) in the 
Beaver, Bettles, and Medfra Quadrangles. U.S. Geol. Surv. OF 
78-94, 1978, 55 pp. 

109. Placer Deposits of Alaska. U.S. Geol. 

Surv. Bull. 1379, 1973, 213 pp. 

110. Heide, H. E., and R. S. Sanford. Churn Drilling at Cape 
Mountain Tin Placer Deposits, Seward Peninsula, Alaska. BuMines 
Rl 4345, 1948, 14 pp. 

111. Sainsbury, C. L, R. Kachadoorian, T. Hudson, T. E. Smith, 
T. R. Richards, and W. E. Todd. Reconnaissance Geologic Maps 



and Sample Data, Teller A-1, A-2, A-3, B-1, B-2, B-3, C-1, and 
Bendeleben A-6, B-6, C-6, D-5, D-6 Quadrangles, Seward 
Peninsula, Alaska. U.S. Geol. Surv. OF 377, 1969, 49 pp. 

112. Cobb, E. H. Summaries of Data on and Lists of References 
to Metallic and Selected Nonmetallic Mineral Occurrences in the 
Bendeleben Quadrangle, Alaska. Supplement »o OF 75-429, Part 
A— Summaries of Data to Jan. 1, 1980. U.S. Geol. Surv. OF 
81-0363-A, 1981, 26 pp. 

113. Thomas, B. I., and W. S. Wright. Investigations of Morelock 
Creek Tin Placer Deposits, Fort Gibbon District, Alaska. BuMines Rl 
4322, 1948, 8 pp. 

114. Mulligan, J. (BuMines). Private communication, 1984; 
available from J. D. Warner, BuMines, Fairbanks, AK. 

115. White, G. E., and G. E. Tolbert. Miller House— Circle Hot 
Springs Area. Ch. in Reconnaissance for Radioactive Deposits in 
East Central Alaska, 1949. U.S. Geol. Surv. Circ. 335, 1954, 4-6 pp. 

116. Maloney, R. P. Investigation of Mercury-Antimony Deposits 
Near Flat, Yukon River Region, Alaska. BuMines Rl 5991, 1962, 44 
pp. 



11 



APPENDIX.— LISTINGS OF LODE AND PLACER OCCURRENCES OF TIN, TANTALUM, 

AND COLUMBIUM IN ALASKA 



Tables A-1 and A-2 list Alaskan lode and placer 
occurrences containing tin. tantalum, and or columbium. 
Where available, abbreviated geologic, geochemical. and 
production data are provided. Generally, the criteria for 
inclusion of a tin occurrence or deposit in these tables were 
(1) the presence of greater than trace amounts of tin and (2) 
a possibility for large, although undefined, volumes of 



material. However, a tew tin occurrences that are in unique 
geologic settings but do not necessarily meet these criteria 
are also included for illustrative purposes. All reported 
occurrences of tantalum and/or columbium are included in 
these tables. The only commodities listed are metals with 
potential economic importance. 



Table A-1. — Lode occurrences 



(For placer occurrences in the vicinity of a listed location, see listings in table A-2 with the same map location number 

in table A-2. placer occurrences have not been reported in the area.) 



the location number does not appear 



Name and 
lat-long location 



Map 
location 
(fig D 



Commodities 
(in order of 
importance) 



Ore grade 

and or 
assay data 



Production 
and/or description 



Refer- 
ences 



NORTHEAST ALASKA TREND 



approx 6735 N. 
141 = 15 W 



Esotuk Glacier. 
69=19N. 144"22W. 


1 


Pb. Zn. Sn. Cu 


W 


Up to 300 ppm Sn and 1 ,500 
ppm W. 


McCali Glacier. 
69 : 18N. 14337 W. 


1 


Cu. Zn, Pb. Sn 




NA 


Bear Mountain. 
68=23 N. 14205W. 


2 


Mo, W, Cb 




60-180 ppm Cb in 
open-ended 200-ft-wide by 
4,000-ft-long geochemical 
soil anomaly. 


Mountain Creek. 
6730N. 141M2W 


3 


Cu. Pb. Zn. Sn 

Ag 


Be, 


140-800 ppm Sn and up to 10 
pet Cu. 


Rapid River lodes. 


3 


U. Sn. Pb. Zn, 


3u 


Several hundred parts per 



million Sn, Pb, and Zn and 
100 ppm U. 



Skarn contains galena, sphalerite, 
axinite, and quartz-tourmaline 
veins. 

Sulfides in deformed quartz veins 
and schist along sheared 
granite-quartz monzonite dike 
contacts. Nearby occurrence of 
fluorite in greisen in granite. 

Soil anomaly corresponds to 
Mo-W-mineralized gossan 
associated with an altered 
porphyry. Pyrochlore identified 
in a pan concentrate. 

Skarn mineralization adjacent to 
rhyolite porphyry sills occurs as 
thin lenses up to 50 ft long. 

Greisen and veins in granite. 



76-77 
76-77 



74 



35-36 
35-36 



BROOKS RANGE TREND 



Unnamed. 
67-30 N. 155O0W 

Unnamed. 
6728 N. 155=06 W 



Unnamed. 
67"-24 N. 15245W 



Kaiueh. 
67-34 N. 15812W 

Kiana. approx 
67=30 N. 16033 W 



Cu. Pb. Zn. Mo. Ag, NA 
Sn 



Au. Ag, Pb, Zn. Sn. 
Mo 



Ag. Cu. Zn. W. Sn. 
B. Be. Bi. Cd. Sb 



Pb. Zn, F. U, Sn, W, 

Ag 
Sn. Cb. Ta 



Up to 55 ppm Au, 55 ppm Ag, 
6.320 ppm Pb. 8.5000 ppm 
Zn, and 450 ppm Sn in rock 
samples. 

700-1.000 ppm Sn and up to 
20 ppm Ag. 1 100- by 300-ft 
zone contains approx 1 pet 
combined W0 3 and Sn. 

NA 

NA 



Contact metamorphic 76 

mineralization near contact 

zone of granite. 
Granite-metamorphic rock contact. 76, 78 

Molybdenite and fluorite 

present. 

Tin disseminated and in skarn 7, 79 

near contact of granite. 



Mineralization in or near granite 80 

contact. 

Unevaluated report of cassiterite, 72-81 

columbite, and tantalite in hills 
north of Kiana, apparently in a 
pegmatite. 



SEWARD PENINSULA TREND 



Setawik Hills area. 


9 


U. Cb. F 


approx 6607 N. 






160=15 W 






Ear Mountain. 


10 


Sn, Cu. Au, Ag, Pb. 


65=56 N. 16612W 




Zn. U. Cb 



Potato Mountain. 
65=39 N. 167=34 W 



Cape Mou r % - 
65=35N. 16TS6W 



fj 



12 



Sn. Cu. Pb. Zn 



Sn 



Several samples contained 
20-90 ppm U and 150-500 
ppm Cb. 

2 pel Sn and 3 pet Cu 
inferred over 1 ,000-ft-long 
by 65-fl-wide zone. 0.01-0 1 
pet Cb identified 
spectrographically in 
mineralized rock at Winfield 
Shaft 

Average grade of mineralized 
zones may be approx 25 
pet Sn Largest zone is 3 to 
10 ft wide and 300 ft long 
and may average 1 pet Sn 

Average of 5- to 5.5-ft channel 
samples was 6 5 pet Sn. 



Altered zones in Selawik Hills 41 

alkaline complex. Cb-U-Ti 

mineral identified. 
Cassiterite in skarn adjacent to 10, 29 

small granite stock. 



Cluster of cassiterite-bearing 4, 10, 

quartz veinlets in tourmalinized 43 

metasedimentary rocks. Small 

irregular mineralized zones. 

2.000 lb Sn reported to have 

been produced (4). 
Small, irregular, podlike 4, 42 

replacement 

cassitente-sericile-quartz- 

tremolite bodies in limestone 

adjacent to granite 12.000 lb 

Sn produced 



•■- ■■■ -■-..-* ace 



12 



Table A-1. — Lode occurrences — Continued 



Name and 
lat-long location 



Map 
location 
(fig. D 



Lost River Mine, 
65°28'N, 167°10'W. 



13 



Bessie Maple, 
65°27'N, 167°12'W. 

Rapid River lode, 
65°24'N, 167°U'W. 



Brooks Mountain, 
65°31'N, 167°09'W. 



13 
13 

13 



Black Mountain, 
65°31'N, 166°43'W. 


14 


Unnamed, 
65°28'N, 


165°37'W. 


15 


Kougarok, 
65°40'N, 


165°13'W. 


16 



Commodities Ore grade D . , 

(in order of and/or ^ r0( ^ cUon t - 

importance) assay data and/or description 

SEWARD PENINSULA TREND— Continued 

Sn, F, W, Be Proven and indicated 695,400 lb Sn produced. Skarn 

reserves: 6.8 MM lb Sn and greisen bodies near or 

grading 0.26 to 1 .3 pet in within granite or related rhyolite 

cassiterite dike and 85 MM dikes. Be deposits located 

lb Sn grading 0.151 pet in zonally away from Sn and F 

cupola. Inferred reserves: deposits. Total proven and 

16.6 MM lb Sn in cassiterite indicated reserves are 91.8 MM 

dike and 4.4 MM lb Sn in lb Sn; total inferred reserves 

Ida Bell Dike. 4.94 MM tons are 21 MM lb Sn. 

fluorite reserves. Grades of 
1 .0 to 2.0 pet Sn mined 
from 1952 to 1955. 

Sn, Ag, Pb, Cu, Sb, NA Sulfide-Sn replacement deposit is 

Zn, W, Be, F flanked by fluoriteberyllium 

deposits. No production noted. 

Be, F, Sn NA Cassiterite encountered at depth 

of several hundred feet in drill 
core. Cupola may underlie area. 
Granite stock intrudes 

Sn, F, W, Pb, Zn, NA metasedimentary rocks. Small 

Cu, Be replacement pod of sulfide 

mineralization noted. 
Sulfide-bearing skarn 

Sn, W, Zn, Pb NA mineralization adjacent to 

altered fault zone near biotite 
granite. Minor greisen 
developed. 
Sn-bearing skarn found in 
Sn > 1, 000 ppm Sn in skarn boulders of frostriven bedrock 

samples. and scattered outcrops. 

Sn, Ta, Cb 



Omilak Mine, 
65°04'N, 162°35'W. 

Foster prospect, 
65°04'N, 162°35'W. 



Granite Mountain, 
65°30'N, 161°08'W. 



21 
21 



23 



Ag, Pb, Sn, Sb 



Ag, Pb, Sn, Au, Sb 



Ag, Pb, Zn, Sn, Cb 



Several ore zones defined 
with 0.36-2.32 pet Sn and 
potential for 0.01-0.03 pet 
Ta and Cb. 



0.2 pet Sn found in rock 
sample. 

High-grade ore contains 
0.1-1.0 pet Sn. Trace to 0.3 
pet Sn irregularly distributed 
throughout 1.7- to 10.4-ft 
drill intersections and 
channel gossan samples. 

Sn detected in 50 pet of 
analyzed soil and rock 
samples. Highest value was 
500 ppm Sn in sulfide veins 
in altered andesite. 
Numerous pan concentrate 
samples on north flank 
contain detectable Cb 



Mineralization consists of steep 
cylindrical bodies and dikes of 
greisenized granite, greisens 
developed along tops of granite 
sills, and veins and stockwork 
in schist. 

Several hundred tons Pb-Ag ore 
produced from lenticular sulfide 
body within limestone. 

Gossan along fracture zone. Sn 
apparently associated with Pb. 



Numerous small argentiferous 
galena-sphalerite-pyrite- 
arsenopyrite-tourmaline 
occurrences in 18-mi-long by 2- 
to 5-mi-wide altered zone in 
andesite and quartz monzonite. 



Refer- 
ences 



4, 10, 
21- 
22, 
82 



4, 10 
10 

4, 10 

10, 83 

10 
84-85 

86 
86 

87, 75 



KOKRINE-HODZANA TREND 



Sithylemenkat, 
66°03'N, 151°03'W. 



Quartz Creek, 
65°16'N, 151°22'W. 



25 



28 



Sn, Cu, Pb, Zn, W, 
Cb 



Ag, Pb, Sn 



0.23 pet Sn in greisen 
samples. Up to 87 ppm Cb, 
0.18 pet Cu, 3 4 pet Pb, 0.4 
pet Zn, and 135 ppm W 
also found in greisen 
samples. 

0.01-0.10 pet Sn in 
mineralized samples. 



Chlorite-magnetite greisen occurs 34 
in rubble at head of east fork of 
Kanuti Kilolitna River. 



Work by the Bureau has shown a NAp 

stockwork of quartz-galena 
veins 0.5-6 in wide along a 
zone approx 1 1 ft wide in 
metasedimentary rocks. Minor 
Ag production. Sn not 
recovered. 



YUKON-TANANA TREND 



Porcupine Dome, 
65°31'N, 145°32'W 

Ketchem Dome, 
65°27'N, 144°42'W. 



33 
33 



Au, Ag, Sn 
Sn, W 



NA 



2.3 pet Sn in high-grade 
samples and 0.05-0.4 pet 
Sn in channel samples of 
vein zones. 0.5 pet Sn in 
pegmatites. 



Au-Ag-bearing quartz veins in 15-16 

metasedimentary rock contain 

cassiterite. 
Greisen and pegmatites 15, 88 

associated with multiple-phase 

biotite granite. 



NA Not available. NAp Not applicable. 



Table A-1. — Lode occurrences — Continued 



13 



Name and 
lat-long location 



Map 
location 
(fig 1) 



Commodities 
(in order of 
importance) 



Ore grade 

and 'or 
assay data 



Production 
and or description 



Refer- 
ences 



YUKON-TANANA TREND— Continued 



Lime Peak. 
6538N. 146-37W. 



34 



Sn. Cb 



Janiksela. 
64°58'N. 147"36 W 

Cosna. 
64°32N. 15V49 W 



35 
37 



Sn 



Pb. Sn. Ag 



Stream sediments contain 
anomalously large amounts 
of Cu, Zn. Ba. Be. La. Mo. 
Pb. Ag, Sn, Th, and U Pan 
concentrate samples from 
streams draining Lime Peak 
summit contained the 
following values, in 
milligrams per pan: 
43.6-561.8 Sn. 24.7-101.4 
W. and 1.2-5.5 Cb. 60-1, 
560 ppm Sn in greisen 
samples. 

NA 



Samples of dumps and 
mineralized rocks contained 
traces to 3 18 pet Sn and 
up to 80 pet Pb and 97 
oz. ton Ag. Sample from 
head of Tin Creek 
reportedly contained 35 pet 
Sn. 14 of 16 rock samples 
collected from Fe-stained 
zones in area contained 
anomalously large 
concentrations of Ag, Sn, 
Bi, Be, Zn, Cu, Mo, and/or 
Pb. 



Multiple-phase biotite granite 15, 

contains chlorite-sencite 37, 

(topaz-tourmaline) greisen 89 

zones. Work by the Bureau has 
shown that greisen vein zones 
up to 300 ft wide can be traced 
for up to 6.000 ft along strike. 



Cassiterite in pegmatite stringer 13 

on contact of mica and graphitic 
schists. 

Apparently veinlike mineralization. 90-91 
Numerous quartz veins and 
rhyolite dikes within andulusite- 
and tourmaline-bearing 
hornfels suggest a granitic body 
at depth. Cassiterite identified. 



KUSKOKWIM TREND 



Win claims. 
63 : 29 N. 155 : 41 W 



Won c a ~ 5 
63 : 12N. 15554W 



Mystery Mountain. 
63=30N. 154<30W 



Telida Mountains. 
63 32N. 15309 W 



38 



39 



40 



Sn. Ag 



Sn. Ag, Au 



Sn. Pb 



41 



Sn 



Beaver Mountains. 
62°SON 15651W 



Russ*ar Wc.' - ; m 
61'40"N. 159'-07'W 



43 



45 



Cb. Sn, Cu, Ag, 



Cu. Au. Ag. Sn 



Sn and sporadic Ag values in 
rock samples. Anomalously 
large concentration of Sn, 
W, Bi, Ag, Zn, Pb, and As 
in pan concentrates. 

Sporadic Sn and Ag values in 
rock samples. > 1.000 ppm 
Sn in pan concentrate 
samples. 

Anomalously large 
concentrations of Sn and Bi 
in rock samples. Local 
gossans contain Pb values 
of several percent. Several 
samples of nonmagnetic 
heavy-mineral concentrates 
contained > 1,000 ppm Sn. 

Anomalously large 
concentrations of Sn, Ag, 
Bi, Cu. Mo, Pb, As, and Be 
in rock samples of 
tourmaline zones. Several 
samples of nonmagnetic 
heavy-mineral 
concentrations contained 
> 1,000 ppm Sn 

200 and 1 ,000 ppm Cb in 2 
samples of sulfide veinlet in 
greisensenized basalt. 100 
ppm Sn in channel samples 
of Cu-Ag-rich 
tourmaline-axinite-greisen 
fracture fillings. 

Typical mineralized rock 
contains 1 pet Cu, 0.1 
oz ton Au, and 1 .0 oz/ton 
Ag, with local Sn values up 
to 1 4 pet 



Linear breccia zones within 59, 92 

hornfelsed argillites. Hypabyssal 
intrusions crop out nearby. 



Breccia and quartz vein stockwork 59, 92 
in horn-felsed argillite near 
partially unroofed intrusion. 

Large area of hornfels cut by 59 

altered rhyolite dikes. Local 
tourmaline flooding and 
tourmalinized breccias. 



Biotite granite intruding clastic 59 

sedimentary rocks and gabbro. 
Widespread tourmaline in 
flat-dipping sheeted zones. 



Veins and greisen zones in 93 

monzonite and overlying basalt. 



800-ft fissure vein within quartz 94-96 

monzonite. 



ALASKA RANGE TREND 



\--.hz 1-ee- 

56'N, 148M7W 



Karmshna distnci. 
63 35N. 15046 W 



Long 1-%e- 
63*11 N. 14939 W 



47 



48 



49 



Zn. Pb. Sn. Ag 



Ag. Au. Sb. Cu. Pb, 
Zn. W. Sn 



Ag. Au. Cu. Bi. Sn 



Average over 350 ft was 1 .4 
pet Zn. 6 pet Pb. 035 
pet Sn. and 3 oz ton Ag. 
Higher grade 8-ft zone 
within horizon contained 1 2 
pet Sn. 

NA 



Up to 700 ppm Sn in rock 
samples 



Volcanogenic massive sulfide 66 

hosted by siliceous exhalite 
(identification uncertain) and 
overlain by graphitic schists. 



Cassiterite- and scheelite-bearing 97 

cobbles reported to be coarse 

and abundant in Caribou and 

Glen Creeks; may suggest a 

lode source nearby 
Sn occurs in arsenopyrite-bearing 98-99 

veins and is disseminated in 

country rock within 300- by 

600-ft area 



NA Not available 



14 



Table A-1— Lode occurrences— Continued 



Name and 
lat-long location 



Ohio Creek, 
63°11'N, 149°55'W. 



Canyon Creek and 
Ready Cash area, 
63°09'N, 149°51'W. 



Tired Pup, approx 
61°20'N, 154°05'W. 



Map 
location 

(fig- D 



Commodities 
(in order of 
importance) 



Ore grade 

and/or 
assay data 



Production 
and/or description 



ALASKA RANGE TREND— Continued 



49 



49 



Sn, Ag, Au, Cu, Pb, 
Zn, W, Cb 



Ag, Sn 



Coal Creek, 
63WN, 149°51'W. 


49 


Sn, Ag, W, Zn 


Tsusena Creek, 
63°01'N, 148°40'W. 


50 


Ag, Cu, Pb, Zn, Sn 


Boulder Creek 
(Purkeypile), 
62°53'N, 152°08'W. 


51 


Sn, Ag 



53 



Sn, U 



>0.10 pet Sn in gresien 
samples. Anomalous Sn, W, 
Ag, Pb, Bi, Be, and Zn in 
stream sediment samples. 

Rock samples of veins 
average 20 oz/ton Ag and 
0.1-1.0 pet Sn. 



Rock samples contain 
0.002-1 .5 pet Sn and are 
reported to average >0.2 
pet Sn. 2 samples assayed 
2.9 and 4.3 oz/ton Ag. 

Channel samples of vein 
yielded 0.5 pet Sn over 4 ft 
and 0.10 pet Sn over 10 ft. 

Up to 18 pet Sn and 230 
oz/ton Ag. 12 of 24 drill hole 
intersections contained 
>0.53 pet Sn; average of 
2.41 pet Sn over a 9-ft vein 
width. 1.11-9.47 oz/ton Ag 
found over lengths of 2-34 ft 
in 9 of 24 drill holes. 

Up to 1 ,000 ppm Sn in stream 
sediment samples. 



Cassiterite-bearing 
muscovite-tourmaline greisen, 
probably limited in extent. 

Vein potential reported in 
hundreds of thousands of tons. 
1 vein, 400 ft of which averaged 
0.5 pet Sn, has about 25,000 
ton potential. 

Inferred ore reserves of >5 MM 
tons of >0.2 pet Sn associated 
with multiple-phase biotite 
granite. Ore body consists of 
stockwork greisen veins. 

Sheeted veins within felsic to 
intermediate volcanic flows, 
tuffs, breccia, and agglomerate. 

300,000 lb Sn proven and 1 .05 
MM lb Sn inferred (24) within 
stockwork of cassiterite-sulfide 
veinlets along a probable 
fracture zone near granite. 
Work by Reed (26) suggests 
substantially lower Sn reserves. 

Reported Sn-U mineralization. 



Refer- 
ences 



39 
99-100 



39 
98-100 



24, 
39, 
101 



88 



25, 

28, 

39, 

102- 

103 



40 



OTHER OCCURRENCES 



Valley of Ten Thousand 
Smokes, 
58°18'N, 155°18'W. 

Copper Mountain, 
60°47'N, 146°34'W. 



Bokan Mountain, 
55°55'N, 132°09'W. 



54 



55 



Sn, Pb, Zn 



Sn 



Rude River, 


56 


Sn 


60°45'N, 145°19'W. 






Tarr Inlet Knob, 


57 


Au, Ag, Cu, Pb, Zn 


58°57'N, 136°54'W. 




Sn 



Johns Hopkins Inlet, 
58 53'N, 137°01'W. 


58 


Cu, Au, Ag, Sn, Vv 


Edelweiss prospect, 
58°04'N, 134°27'W. 


59 


U, Th, Zr, Cs, Cb, 
REE 


Salmon Bay, 
56°19'N, 133°10'W. 


60 


Th, REE, Cb 



61 



U, Th, REE, Pb, Cb, 
Be 



0.019 pet Sn, 0.054 pet Pb, 
and 0.034 pet Zn found in 
precipitate in throat of 
fumarole. 

0.5 pet Sn in sample of 
quartz-cemented breccia 
found in float. 

0.17 pet Sn in pyritiferous 
slate. 

Channel samples up to 
10-ft-long contained 50-200 
ppm Sn and up to 0.68 pet 
Cu, 4.3 pctZn, 0.15 pet Pb, 
100 ppm Ag, and 0.70 ppm 
Au. 

Rock sample contained 
4,100 ppm Cu, 0.15 ppm 
Au, 7 ppm Ag, 700 ppm Sn, 
and 793 ppm W. 

Heavy-mineral concentrate 
samples contained trace to 
major amounts Cb. 

Average of 290 ppm Cb (high 
of 700 ppm) in 5 samples of 
felsic dikes associated with 
mineralized veins. 100 ppm 
Cb in some vein material. 

12 ore samples from Ross 
Adams Mine averaged 1.1 
pet U and 0.01 pet Cb. 
Other prospects contain 
0.003-1 .0 pet Cb associated 
with U mineralization over 
widths probably < 1-6 ft. 



Precipitate consists largely of 
opal, gypsum, and traces of 
arsenic sulfide and barium 
sulfate. 

Host rock may be greenstone. 



Red-stained zone in 
metasedimentary rocks. 

Mineralized fault zones in 
porphyritic granite and quartz 
monzonite. 



Hornfels in float. 



Rare-earth-bearing pegmatite. 

Radioactive carbonate-hematite 
veins and nonradioactive 
rare-earth carbonate veins 
found along 8 mi of coast. 

94,000 tons ore grading approx 1 
pet U mined from Ross Adams 
Mine to 1971. Cb not 
recovered. Mineralization 
consists of disseminated U-Th 
accessory minerals in 
pegmatite, aplite, and 
peralkaline granite; 
hydrothermally deposited U-Th 
minerals in or near fractures; 
and U-Th minerals in interstices 
of quartzite. Columbite and 
pyrochlore identified. 



65 

104 

104 
105 



105 

73 
106-107 

70-71 



REE Rare-earth elements. 















15 








Table A-2. 


—Placer occurrences 






(For lode occurrences in the vicinity of a listed location, see listings in table A-1 with the same map location 


number If the location number does not appear in 






table A-1. 


lode occurrences have not been reported in the area.) 




Name and 
lat-long location 


Map 
location 

(fig 1) 


Commodities 
(in order of 
importance) 


Ore grade 

and or 
assay data 


Production 
and or description 


Refer- 
ences 


NORTHEAST ALASKA TREND 


Bear Mountain. 


2 


W. Cb 




Concentrate from bulk sample 


Downstream from Bear Mountain 


74 


68 23 N. 142 05 W 








of gravel contained 3-12 pet 
WO\ and up to 15 pet Cb. 


lode Pyrochlore-like mineral 












identified. 




Rapid River. 


3 


Sn. W. 


REE. U. Cb. 


1.6-21.0 pet Sn in 


Potentially very large reserves in 


35 


67=38 N. 141=20 W. 








monazite-rich concentrates 
from sluicebox samples. 
0.04-5.7 lb yd 3 Sn. 
0.14-0.75 pet associated W 
and 0.05-0.1 pet Cb. 


basin. 




Porcupine River. 


3 


Sn. REE 


Up to 0.7 pet Sn in pan 


Potential for large, low-grade 


35 


67-21 N. 141=17 W 








concentrate sample of 
ancient channel gravels. 
Cassiterite identified. 


reserves in terrace deposits. 




BROOKS RANGE TREND 


Gold Bench. 


8 


Au. Sn 




Cassiterite in concentrates 


Only Au recovered 


108 


6659 N. 150=19 W 














SEWARD PENINSULA TREND 


Kreoger and Eldorado 


10 


Sn 




Unweighted average for 26 


Creeks drain Ear Mountain stock 


10. 29 


Creeks 








churn drill holes in Kreuger 


and contact zone. No mining 




65=56 N. 166'07'W. 








and Eldorado Creeks was 
0.3 lb yd 3 over 10-ft mining 
section. 


reported. 




Tuttte Creek. 


10 


Sn. Cb 




Trace to 1.2 Ibyd 3 Sn in 


No mining reported 


29 


65=56 N. 1S6=2rW. 








placer samples. Traces of 
Cb also present. 






Potato Creek. 


11 


Sn 




Composite sample of 


do 


43 


65=40N. 167=39W 








concentrate contained 45.22 
pet Sn. Average for 15 
churn drill holes was 0.2 
lb yd 3 Sn in pay streak. 






Buck Creek 


11 


Sn 




Average of 3.9 lb yd 3 Sn in 


From 1902 to 1953, 2,204,600 lb 


43 


65=39 N. 167*31 W. 








pay streak Averages of 1 .0 
and 1.1 lb/yd 3 Sn in upper 
(17 samples) and west (18 
samples) forks of Buck 
Creek, respectively. 


Sn produced from 560,000 yd 3 
of gravel (including Grouse 
Creek). Largely mined out. 




Peluk Creek. 


11 


Sn 




Composite sample of 


Some mining possibly occurred 


10. 43 


6539 N. 1 67=31 W. 








concentrate contained 53 46 
pet Sn. 0.01-0.77 lb/yd 3 Sn. 
Average for 2 churn drill 
holes near creek mouth was 
0.5 Ibyd 3 Sn in pay streak. 


near mouth of creek. 




Sutter Creek. 


11 


Sn 




Abundant Sn occurs near 


Mining extends 1,000 ft from 


10. 43 


6538 N. 167=31 W. 








mouth of Iron Creek. Up to 
90 lb/yd 3 cassiterite 
recovered Average for 30 
churn drill holes was 0.2 
lb yd 3 Sn in pay streak. 


mouth of Iron Creek. 




Iron Creek. 


11 


Sn 




Gravels containing 3.38 lb yd 3 


1.500-ft section along stream bed 


10. 43 


65=39 N. 16733'W 








Sn mined in 1917. Average 
for 1 1 churn drill holes was 
0.6 lb yd 3 Sn in pay streak. 


was hand-mined; unknown 
amount of Sn recovered. 




Oakland C 


11 


Sn 




15 churn drill samples in pay 


Pay streak extends about 1 mi 


43 


65 41 N. 167=36 W 








streak averaged 0.10 lb/yd 3 
Sn. 


along creek near western base 
of Potato Mountain. 




Grouse Creek 


11 


Sn 




Average of 2.9 lb yd 3 Sn in 


See Buck Creek for production. 


10. 43 


65'39 N 167 34W 








pay streak 


Mining extends 5,000 ft 
downstream from mouth of 
Buck Creek Largely mined out. 




. -.-.• I--- 


12 


Sn 




Average for 8 churn drill holes 


No mining reported 


42, 


65'37N. 168D3W 








was 0.18 lb/yd 3 Sn 




109- 
110 
10. 23, 


Boulder Creek. 


12 


Sn. Cb 




Average values in churn 


Pay gravels extend at least 4,000 


6537 N. 167=59 W 








drill-hole lines in pay streak: 
12-17 Ibyd 3 Sn. 22 churn 
drill samples from pay 
streak yielded average of 
10 Ibyd 3 Sn 01-0 1 pet 
Cb detected in a composite 
concentrate sample. 


ft along creek, but no mining 
recorded. 


109- 
110 


Qoodv. - C-ee« 


12 


Sn 




Composite concentrate 


Several hundred pounds 


10, 42, 


65'35N. 167=54W 








sample contained 58 5 pet 
Sn. Average grade of 2 
churn drill samples from pay 
streak at mouth of Goodwin 
Gulch was 4 Ibyd' Sn 
Average for 3 churn drill 
holes m pay streak at 
mouth of Wales Creek was 
1 lb yd 3 Sn. 


cassiterite concentrate 
recovered from narrow 
1.000-ft-long pay streak. 


109- 
110 


REE Rare-earth elements 















16 



Table A-2. — Placer occurrences — Continued 



Name and 
lat-long location 



Map 
location 
(fig- 1) 



Commodities 
(in order of 
importance) 



Ore grade 

and/or 
assay data 



Production 
and/or description 



Refer- 
ences 



SEWARD PENINSULA TREND— Continued 



First Chance Creek, 
65°35'N, 167°56'W. 



Cape Creek, 
65°37'N, 167°59'W. 



Anikovik River, 
65°31'N, 167°36'W. 



Creeks, 

64°57'N, 162°12'W. 



12 



12 



Sn, Cb, Ta 



Sn, Cb, Ta 



13 



Sn, Au 



Cassiterite Creek, 


13 


Sn, W, Cb 


65°28'N, 167°10'W. 






Lost River, 


13 


Sn 


65°27'N, 167°10'W. 






Rapid River, 


13 


Sn 


65°27'N, 167°12'W. 






Kougarok River area 


16 


Au, Sn, Cb 


(Washington and Mascot 






Creeks), 






65°44'N, 164°58'W. 






Humboldt Creek, 


16 


Au, Sn, Cb 


65°49'N, 164°25'W. 






Hannum Creek, 


17 


Au, Sn, Pb 


65°54'N, 163°11'W. 






Otter Creek, 


18 


Au, Sn 


65°06'N, 162°23'W. 






Monument Creek, 


19 


Au, Sn 


64°36'N, 165°30'W. 






Rocky Mountain Creek, 


20 


Au, Sn, W 


64°46'N, 165°12'W, 






Clear and Vulcan 


22 


Cb, Sn, U, W 



20 churn drill holes yielded 
average of 1.0 lb/yd 3 Sn in 
pay streak that extends 
1 ,500 ft up creek from 
mouth. Traces of Cb and Ta 
present. 

32 churn drill holes near 
mouth of creek averaged 
0.2 lb/yd 3 Sn. 48 churn drill 
holes above mouth of First 
Chance Creek averaged 4.5 
lb/yd 3 Sn. Total inferred 
reserves, including gravels 
below First Chance Creek, 
average 2.6 lb/yd 3 Sn. 
Trace of Cb and Ta 
detected. 



31 pet Sn in concentrate. 

156,000 yd 3 of mined 

gravels averaged 0.003 

lb/yd 3 Sn. 
Mine records indicate 3.6 

lb/yd 3 Sn was mined. Trace 

Cb detected. 
0.04-0.35 lb/yd 3 Sn found in 6 

churn drill holes. 
Trace of Sn found in 2 churn 

drill holes. 
Cassiterite in concentrate. 



Concentrates show 60 pet Sn 
and trace Cb. 



Cassiterite and Pb minerals in 

concentrate. 
>5,000 ppm Sn in pan 

concentrate sample. 
Cassiterite reported. 

Cassiterite reported in placer 
concentrates. 

500-800 ppm Cb in pan 
concentrate samples. 1 pet 
Cb found in composite 
samples of concentrates 
from 19 test pits (0.03-0.18 
lb/yd 3 Cb). 



Some past mining is evident. 
Production may be credited to 
Cape Creek. 



Delta-like deposit in beach gravels 
at mouth of Cape Creek and 
alluvial deposits in upper creek. 
Production, including Goodwin 
Gulch, from 1924 to 1975 was 
1 .537 MM lb Sn. Production 
from Cape Creek is presently 
1 50,000-200,000 lb cassiterite 
concentrate per year. 550,250 
lb Sn produced from 1 979 to 
1982. Calculated inferred Sn 
reserves: 2.2 MM lb within 
850,000 yd 3 gravel. 

496 lb Sn produced from within 
0.5 mi of river mouth in 1914 
and 1915. 

93.4 tons Sn recovered from 
52,000 yd 3 of gravel from 1 949 
to 1951. 



Pits irregularly distributed over 
19-mi length of several creeks. 



10, 42, 

109- 

110 



6-7, 10 
23, 42 
109- 
110 



10, 46 



4, 46 



Cassiterite not mined. 


46 


No mining reported 


10, 46 


Intermittent mining to 1968. 
Cassiterite not recovered. 


75, 111 
112 


Coarse cassiterite hampered Au 
recovery. In 1919, a few 
hundred pounds cassiterite was 
saved but not shipped. 

Mined for Au; no cassiterite 
recovered. 

Evidence of past mining; some 
recovery of Sn reported. 

Mined for Au 


84, 
111 

109, 
111 
9, 63 

109 


do 


109 



44 



KOKRINE-HODZANA TREND 



Hogatza, 

66°11'N, 155°43'W. 
Sithylemenkat pluton 

area 

66°03'N, 151°00'W. 



24 
25 



Au, Sn, PGM 
Sn, W, Ta, Cb 



Hot Springs pluton 


26 


Sn 




area, 








66°20'N, 150°46'W. 








Fort Hamlin Hills 


27 


Sn, 


Cb 


pluton area. 








66°07'N, 150°08'N 








Tozimoran and Ash 


29 


Au, 


Sn 


Creeks, 








65°30'N, 153°00'W. 








Melozimoran Creek, 


29 


Au, 


Sn 


65°23'N, 152°49'W. 








Mason Creek, 


30 


Au, 


Sn 


65°11'N, 153°19'W. 









Cassiterite and PGM identified 
in concentrates. 

Trace to 0.404 lb/yd 3 Sn in 
bulk gravel samples from 
upper east fork and 0.08 
lb/yd 3 Sn from main branch 
of Kanuti Kilolitna River. 21 
of 35 placer concentrate 
samples contained average 
of 0.26 pet Cb; 35 
concentrate samples 
contained average of 06 
pet Ta. 

Several pan concentrate 
samples contained 
1,000-7,000 ppm Sn. 

Pan concentrate samples 
contained 7,000->10,000 
ppm Sn and trace Cb. 

Churn drilling showed 0.73 
lb/yd 3 Sn over 650- by 80-ft 
block of ground on 
Tozimoran Creek. 2-3 pet 
Sn in concentrates from 
Ash Creek. 

Trace Sn in lower creek. 

Concentrate recovered in 
1918 averaged 0.5 lb/yd 3 
Sn. 



Dredge operation in glaciofluvial 
deposits recovers Au. 

Sn-bearing gravels in streams 
draining Ray Mountain and 
Sithylemenkat plutons. 



No mining reported 



Creeks draining northwestern 
portion of Fort Hamlin Hills. 

Approx 13,000 lb Sn produced 
from Tozimoran Creek in 
1938-43 and 1983. 
Cassiterite-bearing cobbles 
reported. No production from 
Ash Creek. 

No mining reported 



Unconfirmed report of 1 ton 
cassiterite concentrate 
recovered from 4,000 yd 3 of 
gravel in 1918. No cassiterite 
found in 1944. 



13, 
109 

33-34 



33-34 
33-34 



12, 14, 
18 



14, 18 
14 



PGM Platinum-group metals. 



17 



Table A-2. — Placer occurrences — Continued 



Name and 
lat-long location 



Map 
location 
(fig 1) 



Commodities 

(m order ot 
importance) 



Ore grade 

and or 
assay data 



Production 
and or description 



Refer- 
ences 



KOKRINE-HODZANA TREND— Continued 



Morelock and Bonanza 
Creeks. 
65"19N. 151=20W 



Big Creek. 
64=40 N. 155"29 W 



Birch Creek. 
64=28 N. 1 55=22 W 



Monument Creek. 

64=19 N. 155=23 W 
Poorman Creek. 

64=06 N. 15532 W 
Short Creek. 

64=19N. 15533W 



Spruce Creek. 
64=09 N. 1 55=28 W 

Straight Creek. 
64=23 N. 155=23 W 



31 



Au. Sn 



32 



32 



32 
32 



Au. Sn 



Au. Sn 



Cox Gulch. 
64=40 N. 155=29 W 


32 


Au. Sn 


Crooked Creek. 

64=28 N. 155=23 W 
Fifth of July Creek. 

64=23 N. 155=33W. 


32 
32 


Au. Sn 
Au. Sn 


Rint Creek. 

64=24 N. 155=23 W 
Glacier Creek. 

64=40 N. 155=29W 


32 
32 


Cb 

Au. Sn. Bi 


Greenstone Creek. 
64=18N. 15532W 


32 


Au. Sn 


Long Creek. 
64=23 N. 15532W. 


32 


Au, Sn 


Midnight Creek 
64=19 N. 155=32 W 


32 


Au, Sn 



32 


Sn, Cb 


32 


Au, Sn 


32 


Au. Sn 



Au. Sn 
Au, Sn 



Trace to 0.18 lb Sn per 
square foot of bedrock in 
pay streak at Morelock 
Creek. 15 lb Sn per 
square foot of bedrock 900 
ft above mouth of Bonzana 
Creek. 47 3-65.2 pet Sn in 6 
concentrate samples from 
different parts of pay streak. 

Cassiterite in headwaters. 



Min 0.01-0 04 lb cassiterite 
per square foot of bedrock 
in pay streak. 0.5 lb 
cassiterite per square foot 
of bedrock recovered from 
88,900 ft 2 of underground 
workings. 

0.2-033 lb Sn per square foot 
of bedrock. 



Sn reported 



Sn-bearing area is approx 1.5 mi 
long and 400- to 500-ft wide on 
Morelock Creek and at least 
900 ft up Bonanza Creek. 
Probably about 2 ft of irregularly 
distributed pay streak. Sn 
recovered from a few small 
cuts. 

Pay streak estimated to be 5,000 

ft long, 30 ft wide, and 1-15 ft 

thick. Approx 1.100 lb 

cassiterite concentrate 

recovered. 
At least 5,000 lb cassiterite 

concentrate recovered 1914-36 

Pay streak on bench estimated 

to cover 18 acres. 



Cassiterite very coarse, approx 
1 ,000 lb cassiterite concentrate 
recovered. 

Au mining just above Birch Creek. 



Cassiterite common in 
concentrates. 



Approx 300 lb Sn represents 
incomplete recovery from 
approx 6,000 ft 2 of bedrock. 

Trace Cb detected in Cb not recovered 

concentrates. 

NA 1 50 lb cassiterite concentrate 

recovered. Pay streak 
estimated to cover 12 acres. 

NA Approx 300 lb cassiterite 

recovered 1940-42. Pay streak 
estimated to cover 18 acres. 

NA Cassiterite reported in Au 

concentrates. Pay streak 
estimated to cover 61 acres 
and to be at least 6.4 mi long. 

Cassiterite recovered 7320 lb cassiterite concentrate 

averaged 0.06 lb/yd 3 . produced in 1940-42. 1,037 lb 

concentrate containing 537 lb 
Sn produced in 1917-18. Pay 
streak estimated to cover 9 
acres. 

Trace Sn and Cb detected in Sn and Cb not recovered, 

concentrates. 

Some cassiterite reported. 



Cassiterite is common 

Cassiterite reported. 
NA 



Pay streak estimated to cover 61 

acres. 
In 1918, a few thousand pounds 

of cassiterite was recovered 

from placer workings 1-1.5 mi 

long, 20-40 ft wide, and 10-15 ft 

deep. 
Cassiterite not produced. Pay 

streak estimated to cover 6 

acres. 
Unconfirmed report of cassiterite 

recovered with Au in lower 

portion of creek 



13-14, 
113 



14 



14, 114 



14 

14 
14 

75 

14, 114 

14. 114 
14, 114 

14, 114 



75 

13, 114 

13-14 

13, 114 
14 



YUKON-TANANA TREND 



Yankee Creek. 

6532 N. 145=23 W 
Mastadon Creek. 

65=29 N 145=18 W 

nr'i'€ O ©V*. 

65'31 N. 145=14 W 
Granite Gulch. 

6530 N. 145=12 W 
Harrison Creek. 

65=25N 145'14'W 

Bedrock Creek. 
6530 N 14507W 



Boulder Creek. 
6529 N. 145=03 W 



33 


Au Sn 


33 


Au, Sn 


33 


Au. Sn 


33 


Au. Sn. W 


33 


Au. Sn 



33 



33 



Sn. W 



Au. Sn. W 



Cassi'ente associated with 

placer Au. 
Cassiterite reported in 

concentrates. 
> 1 pet Sn in sluice-box 

sample. 
Sluicebox sample contained 
-40 pet Sn and 4 pet W 
Sluicebox sample from upper 

portion of creek contained 
•1 pet Sn. 
Pan concentrate samples 

showed anomalously large 

concentrations of Sn and 

W 
Estimate of ^2 lb/yd 3 

cassiterite at mine site 63 

pel cassiterite and 2 pet 

scheehte in sluice-box 

concentrates 



Cassiterite not recovered. 


15 




Pay streak in lower valley is 200 ft 

wide and 7-10 ft thick 
Cassiterite not recovered. Pay 

streak has max width of 50 ft. 


15 
15- 


16 


Cassisterite not recovered. 


16 




do 


16 
16 




do 





Pay streaks limited to 200- to 
300-ft wide and 4- to 15-ft-deep 
alluvial gravels. Some 
concentrate recovered 



16 



•.a •.:■ ,.-. ■-.'.<■. 



18 



Table A-2. — Placer occurrences — Continued 



Name and 
lat-long location 



Map 
location 
(fig- D 



Commodities 
(in order of 
importance) 



Ore grade 

and/or 
assay data 



Production 
and/or description 



Refer- 
ences 



YUKON-TANANA TREND— Continued 



Deadwood Creek 
(Switch Creek), 
65°28'N, 144°57'W. 



Ketchem Creek, 
65°29'N, 144°45'W. 

Half Dollar Creek, 

65°25'N, 144°37'W. 
Portage Creek, 

65°26'N, 144°37'W. 

Twin Creek, 

65°02'N, 147°27'W. 
Gilmore Creek, 

64°59'N, 147°25'W. 
Cache Creek, 

65°06'N, 150°48'W. 



Dalton Gulch, 
65WN, 150°50'W. 



Deep Creek area, 
65°04'N, 150°58'W. 



33 



Au, Sn, W 



33 


Au, 


Sn, W 


33 


Au, 


Sn, W 


33 


Au, 


Sn, W, Cb 


35 


Au, 


W, Sn 


35 


Au, 


Sn, Cb 


36 


Au, 


Sn, Cb 


36 


Au, 


Sn, Cb 


36 


Au, 


Sn, Cb 



Ferguson Draw and 
Harter Gulch, 
65°06'N, 150°51'W. 



Gold Basin Creek, 
65°07'N, 150°45'W. 

Idaho and Tofty 
Gulches, 
65°05'N, 150°52'W. 



36 

36 
36 



Au, Sn 

Au, Sn 
Au, Sn, Cb 



Woodchopper Creek, 
65°03'N, 151°01'W. 



36 



Au, Sn, Cb 



Average of 1 -2 lb/yd 3 
concentrates (principally 
wolframite and cassiterite). 
2 sluicebox concentrate 
samples from Switch Creek 
showed approx 10 pet Sn 
and 2 pet W. 

Cassiterite in concentrates. 
>1 pet Sn and >1 pet W in 
sluicebox sample. 

Cassiterite abundant and 
scheelite common. 

Sluicebox sample contained 
>1 pet Sn and trace Cb. 

Cassiterite common 



Trace Cb in concentrates. 

Average of 0.019 lb/yd 3 Cb 
and 2.26 lb/yd 3 Sn found in 
channel samples of tailings. 

Average of 3.9 lb/yd 3 Sn and 
0.0002 lb/yd 3 Cb 2 O s found 
in 5 channel samples of 
tailings. 

Average of 1 .98 lb/yd 3 Sn and 
0.10 lb/yd 3 Cb 2 O s in 26 
channel samples of tailings. 



0.1-0.4 lb cassiterite per 
square foot of bedrock in 
pay streak at Ferguson 
Draw. 4 channel samples of 
tailings from Harter Gulch 
showed an average of 0.27 
lb/yd 3 Sn and trace Cb 2 5 . 

NA 



5 channel samples of tailings 
from Idaho Gulch averaged 
1.0 lb/yd 3 Sn and 0.019 
lb/yd 3 Cb 2 5 . 



Killarney Creek, 
65°07'N, 150°44'W. 


36 


Au, 


Sn 


Cassiterite reported. 


Miller Gulch, 
65°05'N, 150°56'W. 


36 


Au, 


Sn, Cb 


16 channel samples of tailings 
averaged 0.775 lb/yd 3 Sn 
and 0.03 lb/yd 3 Cb 2 5 . Up 
to 7 pet Cb 2 5 in 
concentrates. 


Patterson Creek, 

65°05'N, 150°54'W. 
Sullivan Creek, 

65°07'N, 150°55'W. 


36 
36 


Au, 
Au, 


Sn 
Sn, Cb 


NA 

Tailings average 0.241 lb/yd 3 
Sn and trace Cb. 



12 channel samples of tailings 
averaged 0.72 lb/yd 3 Sn 
and 0.010 lb/yd 3 Cb 2 5 . 
1.2-1.3 lb cassiterite per 
square foot of bedrock 
recovered at south end of 
pay streak. 



Cassiterite recovered from 
concentrates during early 
mining. Pay streak reported to 
be about 9 mi long. 



Cassiterite not recovered. 



..do 



Cassiterite not recovered. 

Bismuthinite and wolframite 

also present. 
May have most abundant 

cassiterite in Fairbanks district. 
Only Au recovered 



5,155 lb cassiterite concentrate 
recovered 1909-56. Aeschymite 
[(Ce, Ca, Fe, Th)(Ti, Cb) 2 (0, 
OH) 6 ] reported. 

3,000 lb cassiterite concentrate 
produced from discontinuous 
pay streaks, 1909-56. 

Columbite [(Fe, Mn)(Nb, Ta) 2 6 ] 
and aeschymite reported. 
64,200 lb concentrate averaging 
56 pet Sn produced from drift 
mining. Pay streak estimated to 
cover 18 acres. 169,400 lb 
indicated Sn reserves in tailings 
of Woodchopper and Deep 
Creeks. 

Harter Gulch and Ferguson Draw 
pay streak estimated to cover 
27 acres. 



Unverified Sn production reported. 
Pay streak estimated to cover 
12 acres. 

Production of cassiterite 
concentrate, 1909-56: 300 lb 
from Idaho Gulch and 19,600 lb 
from Tofty Gulch. Idaho Gulch 
to Tofty Gulch pay streak 
estimated to cover 36 acres. 
157,000 lb indicated Sn 
reserves in tailings from Miller 
Gulch to Tofty Gulch. 

Fine cassiterite abundant for 
1 ,000 ft along creek. 

Columbite and aeschymite in 
concentrate. Production through 
1956 was 101,875 lb cassiterite 
concentrate Long, narrow 
continuous pay streak 
estimated to cover 10 acres. 2 
pay streaks 200 ft apart in 
upper 2,000 ft of workings. 

20,282 lb cassiterite concentrate 
recovered 1909-56. 

215,445 lb cassiterite concentrate 
produced 1909-56. Aeschymite 
also reported. 117,800 lb Sn 
indicated to remain in tailings 
from Sullivan Bench and 
Ferguson Draw. 

40,300 lb cassiterite concentrate 
recovered 1 909-56 from drift 
mining. Lower Woodchopper 
Creek pay streak estimated to 
cover 73 acres. 169,400 lb 
indicated Sn reserves in tailings 
of Woodchopper and Deep 
Creeks. 



15-16 



15-16 

15-16 
15-16 

13 

75 

11, 19- 
32 



11, 19, 
32 



11, 19, 

32, 

114 



11, 19, 

32, 

114 



13, 32 
114 

11, 19, 

32, 

114 



19 

It, 19, 

32, 

114 



11, 19 

11, 19 



11, 19 
114 



NA Not available. 



19 



Table A-2. — Placer occurrences — Continued 



Name and 
lat-long location 



Map 
location 
(fig. D 



Commodities 
(in order of 
importance) 



Ore grade 

and or 
assay data 



Production 
and or description 



Refer- 
ences 



KUSKOKWIM TREND 



Vmasale Mountain. 
62-"38 N. 15759 W 

Malamute Creek. 
62°2B'K 158'OOW 

Marvel Creek. 
60'54 N. 159 30W 



42 



44 



46 



Au. Cb. Sn 



Au. Sn. Hg. W. Cr 



Au. Cb 



Anomalously large 
concentrations of Cb and 
Sn reported in concentrates. 

Cassiterite. cinnabar, scheelite, 
ferberite. chromite. realgar. 
and allanite in concentrates. 

Anomalously large 
concentrations of Cb 
reported in concentrates. 



Only Au recovered 



do 



do 



75 



13, 116 



75 



ALASKA RANGE TREND 



Poorman Creek. 
62 35 N. 150 49 W 



52 



Au. Sn. Pt 



Cassiterite in concentrates. 



1 1 -ft-deep Tertiary gravels on 39, 98, 

lower portion of creek mined for 67 
Au. May have most cassiterite 
in Yentna district. 



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UNITED STATES 

DEPARTMENT OF THE INTERIOR 

BUREAU OF MINES 


A L A S K 


A 


MAP E 




60 100 


150 


Scale, ml 




I983 





LOCATION OF OCCURRENCES, 

PROSPECTS, DISTRICTS, AND AREAS 

CONTAINING TIN (Sn>, TANTALUM (Ta), 

AND/OR COLUMBIUM (Cb) 

1 Esoluk Glacier and McCall 

Glacier 

2 Bear Mountain prospecl Cb 

3 Rapid and Porcupine Rivers area Sn, Cb 

4 Unnamed occurrences Sn 

5 Unnamed occurrences Sn 

6 Kaluich occurrence Sn 

7 Kiana occurrence 

8 Gold Bench occurrence 

9 Selawik Hills area 

10 Ear Mountain area 

11 Potato Mountain area 

12 Cape Mountain area 

13 Lost River Mine area 

14 Black Mountain occurrence 

15 Unnamed occurrence 

16 Kougarok Mountain a 

17 Hannum Creek occur 

18 Otter Creek Mine 

19 Monument Creek occurrence 

20 Rocky Mountain Creek 



Sn. Cb 




?1 


Omilak and Foster prospects 


Sn 




?i» 


Clear and Vulcan Creeks area 


Oh 


Sn 


23 


Granite Mountain area 


Cb 


Sn 


24 


Hogatza occurrence 


Sn 




2b 


Sithylemenkal area 


Sn 


Ta, Cb 


2b 


Hoi Springs plulon area 


sn 




2/ 


Fort Hamlin Hills pluton area 


Sn, 


Cb 


20 


Quartz Creek prospecl 


Sn 




m 


Tozimoran and Ash Creeks ares 


Sn 




3d 


Mason Creek Mine 


Sn 




m 


Morelock Creek and Bonanza 








Creek prospects 


Sn 




32 


Ruby mining district 


Sn 




sa 


Circle mining district 

Lime Peak (Rocky Mountain) 


Sn 




34 








prospect 


Sn, 


3b 


:a 


Fairbanks mining district 


Sn 




3« 


Totty tin belt 


Sn 


;b 


31 


Cosna prospect 


Sn 




m 


Win prospect 


Sn 




39 


Won prospect 


Sn 




40 


Mystery Mountain area 


Kn 




41 


Tellda Mountain area 


Sn 




42 


vinasale Mountain area 


Cb 


Sn 


43 


Beaver Mountains area 


Cb 


Sn 


44 


Malamute Creek occurrence 


Kn 




4b 


Russian Mountains occurrence 


Sn 




46 


Marvel Creek occurrence 


Oti 




4/ 


Sheep Creek prospect 


Sn 




43 


Kantishna mining district 


Sn 




49 


Chulitna area 


Sn 




bO 


Tsusena Creek prospect 


Sn 




b1 


Boulder Creek prospect 


Sn 




bH 


Yentna mining district 


Sn 




63 


Tired Pup pluton area 


Sn 




b4 


Valley ot Ten Thousand Smokes 








area 


Sn 




bb 


Copper Mountain occurrence 


Sn 




46' 


Rude River occurrence 


Sn 




V 


Tarr Inlet Knob occurrence 


Sn 




iS 


Johns Hopkins inlet occurrence 


Sn 




iS 


Edelweiss prospecl 


Oh 




60 


Salmon Bay prospect 


Ob 




61 


Bokan Mountain area 


Cb 





FIGURE 1.— Tin, tantalum, and columblum occurrences In Alaska. 



IC9037 



